Retaining Rings

Aluminum, Extra-Thick, Stress-Free, Delrin^® (Plastic), and Stainless Steel Versions
Compatible with Our Line of Lens Tubes and Mounts
Allow Easy Mounting of Optical Components
M5.5 x 0.5 to SM4 Threading

CMRR

C-Mount (1.00"-32),
Anodized Aluminum

SM05LTRR

SM05 (0.535"-40),
Stress Free

SM1PRR

SM1 (1.035"-40),
Plastic

SM75RR

M75.5 x 0.5,
Anodized Aluminum

SM4RR

SM4 (4.035"-40),
Anodized Aluminum

SM2RRC

SM2 (2.035"-40),
Extra Thick

POLARIS-SM1RR

SM1 (1.035"-40),
Stainless Steel

SM1RRV

SM1 (1.035"-40),
Unanodized Aluminum

Please Wait

Overview
Lens Mounting Guide
Threading Specs
Feedback

Retaining Rings Selection Guide^a

Standard Retaining Rings: Ø5 mm to Ø1/2"

Standard Retaining Rings: Ø13 mm to Ø1"

Standard Retaining Rings: Ø30 mm to Ø1.5"

Standard Retaining Rings: Ø39 mm to Ø2"

Standard Retaining Rings: Ø75 mm to Ø4"

Extra-Thick Retaining Rings

Stress-Free Retaining Rings

Plastic Retaining Rings

Unanozided Aluminum Retaining Rings, Vacuum Compatible

Stainless Steel Retaining Rings, Vacuum Compatible

Click "More" in each section of the table to view available retaining rings. Use the links in the table header to jump to a detailed web presentation with complete information for each retaining ring.

Features

Standard (Aluminum) Retaining Rings Available for Optics Ranging from Ø5 mm to Ø4"
Extra-Thick SM05-, SM1-, and SM2-Threaded Retaining Rings for High-Curvature Lenses
Stress-Free Retaining Rings are Compatible with the SM05, SM1, and SM2 Thread Standards
Delrin^®* (Plastic) SM05- and SM1-Threaded Retaining Rings Provide Gentler Contact with Optic Surface
Unanodized Aluminum SM05-, SM1-, and SM2-Threaded Retaining Rings for Our Aluminum Vacuum-Compatible Components
Stainless Steel SM05-, SM1-, and SM2-Threaded Retaining Rings for Our SM-Threaded Polaris^® Mounts
Standard SM05-, SM1-, and SM2-Threaded Retaining Rings Available in Packs of 5 or 10

Thorlabs offers a wide selection of Retaining Rings for securing optical components into our threaded mounts, lens tubes, and unmounted optic adapters. Two retaining rings can be used to secure the optical component inside the center of a lens tube: one as a stopper and the other to lock in the component.

Depending on the size needed, these retaining rings are available in one or more of the following types: standard balck anodized aluminum, unanodized aluminum, extra-thick, stress-free, plastic, or stainless steel. For a table of available options, please see the Retaining Rings Selection Guide to the right.

We offer extra-thick (5 mm) retaining rings which provide easier mounting for high-curvature lenses, such as aspheric lenses and condenser lenses (see the Lens Mounting Guide tab for more information). Our Stress-Free Retaining Rings (Item #'s SM05LTRR, SM1LTRR, and SM2LTRR) have a rubber O-ring that provides a light-tight seal around the optical components. The SM05PRR and SM1PRR Plastic Retaining Rings are produced from Delrin to provide gentler contact with an optic's surfaces than our standard retaining rings. Please keep in mind that due to the increased thickness of the stress-free and plastic retaining rings, the thickness of the optic that can be accommodated in the mount may be reduced.

Two vacuum-compatible options are available and intended for use with threaded components of the same material: unanodized aluminum retaining rings for aluminum vacuum-compatible components and stainless steel retaining rings are ideal for use with our SM-threaded high-stability Polaris mirror mounts.

Thorlabs also offers a line of fixed-diameter and adjustable spanner wrenches for rings for optic diameters from 5 mm to 3" and spanner bits for SM05, SM1, SM1.5, SM2, and SM3 retaining rings. For using multiple thread types in the same setup, please see our extensive line of thread adapters.

For ordering convenience, the SM05RR and SM1RR Standard Retaining Rings are available in packs of 10, and the SM2RR Standard Retaining Ring is available in packs of 5.

*Delrin^® is a registered trademark of DuPont Polymers, Inc.

Thorlabs' retaining rings are used to secure unmounted optics within lens tubes or optic mounts. These rings are secured in position using a compatible spanner wrench. For flat or low-curvature optics, standard retaining rings manufactured from anodized aluminum are available from Ø5 mm to Ø4". For high-curvature optics, extra-thick retaining rings are available in Ø1/2", Ø1", and Ø2" sizes.

Extra-thick retaining rings offer several features that aid in mounting high-curvature optics such as aspheric lenses, short-focal-length plano-convex lenses, and condenser lenses. As seen in the animation to the right, the guide flange of the spanner wrench will collide with the surface of high-curvature lenses when using a standard retaining ring, potentially scratching the optic. This contact also creates a gap between the spanner wrench and retaining ring, preventing the ring from tightening correctly. Extra-thick retaining rings provide the necessary clearance for the spanner wrench to secure the lens without coming into contact with the optic surface.

Click to Enlarge

Threading Specifications

The following is a general overview of screw threading. For more details regarding specifications and dimensions, please consult the Machinery's Handbook, available for purchase at many bookstores.

Features of a Thread
A thread consists of three repeating features: a crest, flank, and root (see drawing to the right). Except in special cases, threads have symmetrical sides inclined at equal angles when a vertical line is drawn through the center of a crest or root. The distance between corresponding points on adjacent threads is known as the pitch of the thread. The flank angle is defined as the angle the flank makes with a perpendicular ray drawn from the screw axis. Unless otherwise stated, threads have a flank angle of 30°, resulting in a total angle between flanks of 60°. Each feature is shown in the diagram to the right.

The major diameter is taken from the crests of a thread while the minor diameter is taken from the roots. For most screws, crests and roots do not terminate at a sharp point, so crest and root truncation values are included in the definitions of major and minor diameter. The pitch diameter is approximately halfway between the major and minor diameters.

Thread Form
A thread form is a set of rules that define the features' scale relative to one another. Common thread forms include the Unified Screw Thread Form, used in the United States of America and measured in imperial units, and the ISO Metric Screw Thread Form, used in many parts of the world and measured with the International System of Units. There are many thread forms in the Unified screw thread standard designated by either UN, which defines a flat root contour, or UNR, which defines a round root contour. These can be further described by appending more letters. For example, an extremely fine thread with a flat root contour is designated UNEF. Those forms which are not standardized by the Unified screw thread system are designated UNS.

Thread Series
Most screws are identified by their thread series. Thread series are denoted by the major diameter and density of threads. Unified threads specify density in threads per inch, while Metric threads specify the thread pitch. For example, in the Unified nomenclature, a 1/4"-20 cap screw has a 1/4" diameter barrel and the pitch is 20 threads per inch (TPI). In metric nomenclature, an M4 x 0.7 cap screw has a 4 mm barrel and the pitch is 1 thread per 0.7 mm. The term M4 x 0.7 is often shortened to just M4.

Unified Thread Class Tolerancing
Location	Loose	Optimal	Strict
Internal	1B	2B	3B
External	1A	2A	3A

Metric Thread Tolerance Positions
Location	Loose	Optimal	Strict
Internal	-	G	H
External	e or f	g	h

Metric Thread Tolerance Grades
Dimension	Location	Tolerance Grades^a
Minor Diameter	Internal	4, 5, 6, 7, 8
Major Diameter	External	4, 6, 8
Pitch Diameter	Internal	4, 5, 6, 7, 8
Pitch Diameter	External	3, 4, 5, 6, 7, 8, 9

The tolerance becomes looser as the grade increases. The underlined grades are used with normal lengths of thread engagement.

Thread Class
The tolerances and allowances on a thread series are given by a thread class. Unified thread classes are alphanumeric identifiers starting with a number from 1 through 3, where 1 is the loosest tolerance and 3 is the tightest, and either A for external threading or B for internal threading.

Metric threads have a slightly more complex tolerancing method that uses tolerancing grades, designated by a number 3 through 9; and tolerancing positions, which use letters e through h. Grades provide a measure of the tolerance itself: the smaller the number, the tighter the tolerance. Positions denote the distance of the tolerance from the pitch diameter. Uppercase positioning letters indicate internal threads while lowercase positioning letters indicate external threads.

Quoting from the Machinery's Handbook, 29th Edition, p. 1885: "To designate the tolerance class, the grade and position of the pitch diameter is shown first followed by that for the major diameter in the case of the external thread or that for the minor diameter in the case of the internal thread, thus 4g6g for an external thread and 5H6H for an internal thread. If the two grades and positions are identical, it is not necessary to repeat the symbols, thus 4g, alone, stands for 4g4g and 5H, alone, stands for 5H5H."

Thorlabs' SM Series Threads
Threading specifications for our SM threads, utilized in our lens tube and cage system components, are given below so that you can machine mating components to suit your application. Most SM series threads utilize a non-standard Unified thread form, indicated by the letters UNS, with a 30° flank angle and a thread class of 2A and 2B. The exception is our SM30 series thread, which is a Metric thread form with a 30° flank angle and a tolerance of 6H/6g. We also offer products with C-Mount and RMS threads, and the specifications for these threads are given below for reference. Please note that other manufacturers may have different tolerances for C-Mount and RMS threads. For other thread specifications that are not listed here, please contact Tech Support.

SM05 Threading: Ø1/2" Lens Tubes, 16 mm Cage Systems
External Thread, 0.535"-40.0 UNS-2A		Internal Thread, 0.535"-40.0 UNS-2B
Max Major Diameter	0.5340"	Min Major Diameter	0.5350"
Min Major Diameter	0.5289"	Min Pitch Diameter	0.5188"
Max Pitch Diameter	0.5178"	Max Pitch Diameter	0.5230"
Min Pitch Diameter	0.5146"	Min Minor Diameter (and 83.3% of Thread)	0.508"
Max Minor Diameter	0.5069"	Max Minor Diameter (and 64.9% of Thread)	0.514"

RMS Threading: Objective, Scan, and Tube Lenses
External Thread, 0.800"-36.0 UNS-2A		Internal Thread, 0.800"-36.0 UNS-2B
Max Major Diameter	0.7989"	Min Major Diameter	0.8000"
Min Major Diameter	0.7934"	Min Pitch Diameter	0.7820"
Max Pitch Diameter	0.7809"	Max Pitch Diameter	0.7866"
Min Pitch Diameter	0.7774"	Min Minor Diameter (and 83.3% of Thread)	0.770"
Max Minor Diameter	0.7688"	Max Minor Diameter (and 64.9% of Thread)	0.777"

C-Mount Threading: Machine Vision Lenses, CCD/CMOS Cameras
External Thread, 1.000"-32.0 UN-2A		Internal Thread, 1.000"-32.0 UN-2B
Max Major Diameter	0.9989"	Min Major Diameter	1.0000"
Min Major Diameter	0.9929"	Min Pitch Diameter	0.9797"
Max Pitch Diameter	0.9786"	Max Pitch Diameter	0.9846"
Min Pitch Diameter	0.9748"	Min Minor Diameter (and 83.3% of Thread)	0.966"
Max Minor Diameter	0.9651"	Max Minor Diameter (and 64.9% of Thread)	0.974"

SM1 Threading: Ø1" Lens Tubes, 30 mm Cage Systems
External Thread, 1.035"-40.0 UNS-2A		Internal Thread, 1.035"-40.0 UNS-2B
Max Major Diameter	1.0339"	Min Major Diameter	1.0350"
Min Major Diameter	1.0288"	Min Pitch Diameter	1.0188"
Max Pitch Diameter	1.0177"	Max Pitch Diameter	1.0234"
Min Pitch Diameter	1.0142"	Min Minor Diameter (and 83.3% of Thread)	1.008"
Max Minor Diameter	1.0068"	Max Minor Diameter (and 64.9% of Thread)	1.014"

SM30 Threading: Ø30 mm Lens Tubes
External Thread, M30.5 x 0.5 – 6H/6g		Internal Thread, M30.5 x 0.5 – 6H/6g
Max Major Diameter	30.480 mm	Min Major Diameter	30.500 mm
Min Major Diameter	30.371 mm	Min Pitch Diameter	30.175 mm
Max Pitch Diameter	30.155 mm	Max Pitch Diameter	30.302 mm
Min Pitch Diameter	30.059 mm	Min Minor Diameter (and 83.3% of Thread)	29.959 mm
Max Minor Diameter	29.938 mm	Max Minor Diameter (and 64.9% of Thread)	30.094 mm

SM1.5 Threading: Ø1.5" Lens Tubes
External Thread, 1.535"-40 UNS-2A		Internal Thread, 1.535"-40 UNS-2B
Max Major Diameter	1.5339"	Min Major Diameter	1.535"
Min Major Diameter	1.5288"	Min Pitch Diameter	1.5188"
Max Pitch Diameter	1.5177"	Max Pitch Diameter	1.5236"
Min Pitch Diameter	1.5140"	Min Minor Diameter (and 83.3% of Thread)	1.508"
Max Minor Diameter	1.5068"	Max Minor Diameter (and 64.9% of Thread)	1.514"

SM2 Threading: Ø2" Lens Tubes, 60 mm Cage Systems
External Thread, 2.035"-40.0 UNS-2A		Internal Thread, 2.035"-40.0 UNS-2B
Max Major Diameter	2.0338"	Min Major Diameter	2.0350"
Min Major Diameter	2.0287"	Min Pitch Diameter	2.0188"
Max Pitch Diameter	2.0176"	Max Pitch Diameter	2.0239"
Min Pitch Diameter	2.0137"	Min Minor Diameter (and 83.3% of Thread)	2.008"
Max Minor Diameter	2.0067"	Max Minor Diameter (and 64.9% of Thread)	2.014"

SM3 Threading: Ø3" Lens Tubes
External Thread, 3.035"-40.0 UNS-2A		Internal Thread, 3.035"-40.0 UNS-2B
Max Major Diameter	3.0337"	Min Major Diameter	3.0350"
Min Major Diameter	3.0286"	Min Pitch Diameter	3.0188"
Max Pitch Diameter	3.0175"	Max Pitch Diameter	3.0242"
Min Pitch Diameter	3.0133"	Min Minor Diameter (and 83.3% of Thread)	3.008"
Max Minor Diameter	3.0066"	Max Minor Diameter (and 64.9% of Thread)	3.014"

SM4 Threading: Ø4" Lens Tubes
External Thread, 4.035"-40 UNS-2A		Internal Thread, 4.035"-40.0 UNS-2B
Max Major Diameter	4.0337"	Min Major Diameter	4.0350"
Min Major Diameter	4.0286"	Min Pitch Diameter	4.0188"
Max Pitch Diameter	4.0175"	Max Pitch Diameter	4.0245"
Min Pitch Diameter	4.0131"	Min Minor Diameter (and 83.3% of Thread)	4.008"
Max Minor Diameter	4.0066"	Max Minor Diameter (and 64.9% of Thread)	4.014"

Posted Comments:

Travis Briles (posted 2023-08-11 13:49:02.8)

It would be very useful if you made the stress free retaining ring in the 3" size. Currently the largest size is 2". Could several of these be purchased as custom items?

jdelia (posted 2023-08-14 09:03:41.0)

Thank you for your feedback. While we currently do not offer these as part of our standard catalog, I have forwarded your request to our design engineers via our internal suggestion forum. I have also reached out to you directly regarding the possibility of quoting these out to you as a custom part.

Nina Krainova (posted 2023-05-05 00:18:57.34)

Hello! I have been wondering for awhile, why these retaining rings have notches only on one side, won't having them on both sides be more logical? Won't lie, I found myself a couple of times putting them in lens tube by hand (it's faster) to find out a bit later that I put it in wrong side and can't tighten it with a wrench.

jdelia (posted 2023-05-08 01:41:18.0)

Thank you for contacting Thorlabs. Typically, access to only one side of the ring is required for the spanner wrench to install and it properly. I will be passing your request along to our design engineers through our internal suggestion forum for future consideration as a feature. In the meantime, I have reached out to you directly to further discuss your application.

Jasper Phelps (posted 2023-03-21 13:25:36.87)

This item was not packaged with sufficient padding and most of the rings were bent and unusable. I ordered 2 packs of 5 rings but only 2 out of the 10 were usable. The packs of 5 were in a box with many other components of my order, and I guess they got squished by the other items in the box. Don't worry about any sort of reimbursement or sending me new ones, I just wanted to provide the feedback for your information.

jdelia (posted 2023-03-21 03:16:27.0)

Thank you for contacting Thorlabs and for providing this valuable feedback. We sincerely apologize for the inconvenience here and will look toward improving this in the future. I have contacted you directly to discuss this further.

Yoshifumi Doi (posted 2022-09-21 10:42:55.027)

I would like information on relation between fastening torque and axial force using anodized aluminum rings and tubes. The information is only for reference. Coefficient of friction will be also appreciated. Our objective of the information is to estimate loads on optical elements. Thank you in advance for your cooperation.

Mikael Malmström (posted 2021-01-26 04:26:13.66)

can you add the specs for M100.75x0.5 and SM4 in the "Threading Specs"?

YLohia (posted 2021-01-27 11:23:04.0)

Hello, thank you for your feedback. We are working on adding the SM4 thread specs to the "Threading Specs" tab. This tab is intended to display information about thread types created by Thorlabs, not the standard Mxxx thread types. That being said, all thread specs can be accessed by clicking on the blue info icons next to part number tables.

Xiaoyu Jiang (posted 2019-07-24 19:18:39.24)

Our lab is trying to build a system in UHV and we are using some SM05RR rings. We are worried about the compatibility for the black anodized rings with UHV. Can you give some technical suggestions on this issue or provide quotes for UHV compatible retaining rings? Thanks.

YLohia (posted 2019-07-25 10:03:18.0)

Hello, we do not recommend using SM05RR retaining rings in UHV applications due to outgassing of the anodization. Our stainless steel POLARIS-SM05RR retaining rings designed for our POLARIS mounts would be a more suitable choice.

chris (posted 2017-06-12 08:51:23.777)

Unclear what I need. Have 30mm unmounted optics and want to install in SM2 tube. What item do I need? Thanks. CHris

tfrisch (posted 2017-06-26 10:34:41.0)

Hello, thank you for contacting Thorlabs. You may want to look at AD2-30 or SM2AD30 on our 2" adapters page: https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=5324

rachid (posted 2017-05-03 22:29:46.17)

I am planing to buy polarizer "LPVISE200-A" with a rotating mount "RSP2". what kind of ring is suitable for me so I can hold the polarizer ? Regards, Rachid

tcampbell (posted 2017-05-03 11:53:06.0)

Response from Tim at Thorlabs: The RSP2 rotation mount has an SM2-threaded bore, which accepts SM2RR retaining rings. However, one SM2RR retaining ring is already included with the RSP2 mount to hold the optic against the mount's fixed retention lip.

christoph.bohr (posted 2016-11-03 10:35:46.07)

Given the small torque used in tightening down the retaining rings I wonder if there is a recommended method for securing the retaining rings to keep them from working loose in a high vibration environment. Something like a thread locker but ideally something that still allows disassembly for service and does not interfere with the lens and coating material. regards C. Bohr

tfrisch (posted 2016-11-04 09:26:04.0)

Hello, thank you for contacting Thorlabs. I will reach out to you directly to discuss your high vibration application.

tmorgus (posted 2016-06-10 16:34:03.81)

Hello Cbrideau, Dito. This was a project that kept slipping to the back burner since there are alternative solutions. But it is nice to finally have the right solution available for highly curved optics. Sincerely, Tyler Mechanics Business Unit Leader

cbrideau (posted 2016-06-10 15:32:13.92)

Glad to see these thick rings finally available! I'll be talking to my local distributor about getting some for holding large condenser lenses.

cbrideau (posted 2016-02-22 11:54:32.26)

Would love to be able to get the extra-thick version of these for mounting Condenser lenses. These rings are used in your pre-built collimation mounts but thus far you don't sell them individually.

schach (posted 2014-08-13 14:01:20.563)

Guten Tag, welches Gewinde besitzt der Sicherungsring SM18RR? In der Liste finde ich die Angabe M18,5x0,5, die dazugehörige Angabe in der Zeichnung lautet 0,750-40! Vielen Dank im voraus. Mit freundlichen Grüßen C.Schach

jlow (posted 2014-08-13 08:48:36.0)

Response from Jeremy at Thorlabs: Thank you for bringing this to our attention. The correct thread is 0.750"-40 for the SM18RR. We will correct the thread call out on the website.

nick (posted 2013-02-01 12:08:06.75)

Can you please clarify what the o-ring material is (for product SM05LTRR), as well as its lifetime rating in an ambient environment?

tcohen (posted 2013-02-06 15:26:00.0)

Response from Tim at Thorlabs: The O-Ring is Buna-N. We have updated our presentation to include this information.

tcohen (posted 2012-09-18 15:10:00.0)

Response from Tim at Thorlabs to Luis: These have a black anodized finish which is typically not suitable for UHV. I will contact you directly to discuss your requirements and provide a quote for a vacuum compatible version.

lgml1 (posted 2012-09-17 16:22:31.0)

Hello, this is very useful. I just wish to ask whether any the SM17RR is suitable for being used in ultra high vacuum (I'm designing a customised tuve for holding the lens). Cheers, Luis

tcohen (posted 2012-07-19 13:04:00.0)

Response from Tim at Thorlabs: Thank you for contacting us. This will depend on the lens dimensions and material. Qualitatively, you want to use the minimum amount of torque required to secure the optic as overtightening will induce stress birefringence. That being said, the retaining rings should hold the optic in a much less stressful way at the point of contact than a setscrew for example. Stress-free retaining rings were designed with this in mind. I will contact you directly to continue this conversation.

sebastien.avila (posted 2012-07-17 10:38:21.0)

Hello, What is the tightening torque that should not be exeed while using an SM18RR on a 18mm diameter convex lens? We want to have a standar procedure to mounting these lenses and we need to stablish the maximum torque allowed. Thank you.

tcohen (posted 2012-06-19 10:55:00.0)

Response from Tim at Thorlabs: The external thread specifications for the M15.5-0.5 thread used on our SM15RR are Major Max 15.479, Major Min 15.371, Minor Max 14.938, Minor Min 14.757, Pitch Max 15.155 and Pitch Min 15.065.

jbowen (posted 2012-06-18 08:51:32.0)

I would like to know the thread specification for this part. Please provide the minor, major, and pitch diameters with the minimum and maximum tolerances for each dimension.

Standard Retaining Rings: Ø5 mm to Ø1/2"

Zoom

Standard Retaining Rings for Optics Ranging
from Ø5 mm to Ø1/2"
Compatible with our Optic Mounts and Lens Tubes
SM05RR Retaining Rings Available in 10 Packs

Our Standard Retaining Rings are manufactured from anodized aluminum and are offered in sizes to match our optic mounts and lens tubes. They maximize the clear aperture while providing sufficient holding force. Securing an optic using a retaining ring is a stable method for holding the optic since the optic is retained along its entire edge instead of just at a few points. Each retaining ring is machined with two slots for compatibility with our selection of spanner wrenches.

Item #	Thread	Thickness	Compatible Spanner Wrench	Compatible Optic Mounts	Clear Aperture
SM5RR	M5.5 x 0.5	0.07" (1.7 mm)	SPW205 or SPW801	LMR5(/M), AD5T, CPN05, SP07, MLH5(/M), or SM1AD5	Ø0.15" (Ø3.8 mm)
SM6RR	M6.5 x 0.5	0.07" (1.7 mm)	SPW206 or SPW801	LMR6(/M), AD6T, CPN06, SP08, MLH6(/M), or SM1AD6	Ø0.19" (Ø4.8 mm)
SM7RR	M7.5 x 0.5	0.07" (1.7 mm)	SPW207 or SPW801	LMR7(/M), AD7T, SP09, MLH7(/M), or SM1AD7	Ø0.23" (Ø5.8 mm)
SM8RR	M8.5 x 0.5	0.07" (1.7 mm)	SPW208 or SPW801	LMR8(/M), AD8T, CPN08, SP10, MLH8(/M), or SM1AD8	Ø0.27" (Ø6.9 mm)
SM9RR	M9.5 x 0.5	0.07" (1.7 mm)	SPW209 or SPW801	LMR9(/M), AD9T, CPN09, SP11, MLH9(/M), or SM1AD9	Ø0.31" (Ø7.9 mm)
SM10RR	M10.5 x 0.5	0.07" (1.7 mm)	SPW210 or SPW801	LMR10(/M), AD10T, SP12, MLH10(/M), or SM1AD10	Ø0.35" (Ø8.8 mm)
SM11RR	M11.5 x 0.5	0.07" (1.7 mm)	SPW211 or SPW801	AD11T, SP13, or SM1AD11	Ø0.36" (Ø9.1 mm)
SM12RR	M12.5 x 0.5	0.07" (1.7 mm)	SPW801	SP14	Ø0.40" (Ø10.2 mm)
SM05RR(-P10)	SM05 (0.535"-40)	0.07" (1.7 mm)	SPW603, SPW603L, or SPW801	Any Internally SM05-Threaded Mount	Ø0.44" (Ø11.0 mm)

Based on your currency / country selection, your order will ship from Newton, New Jersey

+1 Qty Docs Part Number - Universal Price Available

SM5RR M5.5 x 0.5 Retaining Ring for Ø5 mm Lens Mounts

$11.53

Item	Thread	Optic Size
SM5RR	M5.5 x 0.5	Ø5 mm
SM6RR	M6.5 x 0.5	Ø6 mm
SM7RR	M7.5 x 0.5	Ø7 mm
SM8RR	M8.5 x 0.5	Ø8 mm
SM9RR	M9.5 x 0.5	Ø9 mm
SM10RR	M10.5 x 0.5	Ø10 mm
SM11RR	M11.5 x 0.5	Ø11 mm
SM12RR	M12.5 x 0.5	Ø12 mm
SM05RR	SM05 (0.535"-40)	Ø1/2" and Ø12.5 mm

Item #	Thread	Thickness	Compatible Spanner Wrench	Compatible Optic Mounts	Clear Aperture
SM13RR	M13.5 x 0.5	0.07" (1.7 mm)	SPW801	AD13T or SM1AD13	Ø0.43" (Ø10.9 mm)
SM14RR	M14.5 x 0.5	0.07" (1.7 mm)	SPW801	AD14T or SM1AD14	Ø0.46" (Ø11.7 mm)
SM15RR	M15.5 x 0.5	0.07" (1.7 mm)	SPW801	LMR15(/M), AD15T, CPN15, or SM1AD15	Ø0.50" (Ø12.7 mm)
SM16RR	M16.5 x 0.5	0.08" (2.0 mm)	SPW801	AD16T or SM1AD16	Ø0.54" (Ø13.6 mm)
SM17RR	M17.5 x 0.5	0.08" (2.0 mm)	SPW801	AD17T or SM1AD17	Ø0.57" (Ø14.5 mm)
SM18RR	0.750"-40	0.08" (2.0 mm)	SPW801	LMR18(/M), AD18T, CPN18, or SM1AD18	Ø0.62" (Ø15.7 mm)
SM19RR	M19.5 x 0.5	0.08" (2.0 mm)	SPW801	AD19T or SM1AD19	Ø0.64" (Ø16.3 mm)
RMSRR	0.800"-36	0.07" (2.0 mm)	SPW801	OMR(/M), CP42(/M),or HCS013	Ø0.67" (Ø17.0 mm)
SM20RR	M20.5 x 0.5	0.08" (2.0 mm)	SPW801	LMR20(/M), AD20T, CPN20, or SM1AD20	Ø0.68" (Ø17.3 mm)
CMRR	1.00"-32	0.08" (2.0 mm)	SPW801	CMR(/M) or CP13(/M)	Ø0.87" (Ø22.0 mm)
SM1RR(-P10)	SM1 (1.035"-40)	0.08" (2.0 mm)	SPW606, SPW602, or SPW801	Any Internally SM1-Threaded Mount	Ø0.90" (Ø22.9 mm)

Item #	Thread	Thickness	Compatible Spanner Wrench	Compatible Optic Mounts	Clear Aperture
SM30RR	SM30 (M30.5 x 0.5)	0.08" (2.0 mm)	SPW607 or SPW801	Any Internally SM30-Threaded Mount	Ø1.10" (Ø27.9 mm)
SM31RR	M31.5 x 0.5	0.08" (2.0 mm)	SPW801	SM2AD31	Ø1.14" (Ø29.0 mm)
SM32RR	M32.5 x 0.5	0.08" (2.0 mm)	SPW801	SM2AD32 or C32	Ø1.18" (Ø30.0 mm)
SM33RR	M33.5 x 0.5	0.08" (2.0 mm)	SPW801	SM2AD33	Ø1.22" (Ø31.0 mm)
SM34RR	M34.5 x 0.5	0.08" (2.0 mm)	SPW801	SM2AD34	Ø1.26" (Ø32.0 mm)
SM35RR	M35.5 x 0.5	0.08" (2.0 mm)	SPW801	SM2AD35	Ø1.30" (Ø33.0 mm)
SM36RR	M36.5 x 0.5	0.08" (2.0 mm)	SPW801	SM2AD36	Ø1.34" (Ø34.0 mm)
SM37RR	M37.5 x 0.5	0.08" (2.0 mm)	SPW801	SM2AD37	Ø1.38" (Ø35.0 mm)
SM38RR	M38 x 0.5	0.10" (2.5 mm)	SPW801	SM2A20 or WFA4111	Ø1.38" (Ø34.9 mm)
SM1.5RR	SM1.5 (1.535"-40)	0.10" (2.5 mm)	SPW608 or SPW801	Any Internally SM1.5-Threaded Mount	Ø1.38" (Ø34.9 mm)

Item #	Thread	Thickness	Compatible Spanner Wrench	Compatible Optic Mounts	Clear Aperture
SM39RR	M39.5 x 0.5	0.10" (2.5 mm)	SPW801	SM2AD39	Ø1.44" (Ø36.5 mm)
SM40RR	M40.5 x 0.5	0.10" (2.5 mm)	SPW801	SM2AD40	Ø1.47" (Ø37.5 mm)
SM41RR	M41.5 x 0.5	0.10" (2.5 mm)	SPW801	SM2AD41	Ø1.51" (Ø38.5 mm)
SM42RR	M42.5 x 0.5	0.10" (2.5 mm)	SPW801	SM2AD42	Ø1.55" (Ø39.5 mm)
SM43RR	M43.5 x 0.5	0.10" (2.5 mm)	SPW801	SM2AD43	Ø1.59" (Ø40.5 mm)
SM44RR	M44.5 x 0.5	0.10" (2.5 mm)	SPW801	SM2AD44	Ø1.63" (Ø41.5 mm)
SM45RR	M45.5 x 0.5	0.10" (2.5 mm)	SPW801	LMR45 (LMR45/M) or SM2AD45	Ø1.67" (Ø42.4 mm)
SM46RR	M46.5 x 0.5	0.10" (2.5 mm)	SPW801	SM2AD46	Ø1.71" (Ø43.5 mm)
SM47RR	M47.5 x 0.5	0.10" (2.5 mm)	SPW801	SM2AD47	Ø1.75" (Ø44.5 mm)
SM48RR	M48.5 x 0.5	0.10" (2.5 mm)	SPW801	SM2AD48	Ø1.79" (Ø45.5 mm)
SM2RR(-P5)	SM2 (2.035"-40)	0.10" (2.5 mm)	SPW604 or SPW801	Any Internally SM2-Threaded Mount	Ø1.90" (Ø48.3 mm)

Item #	Thread	Thickness	Compatible Spanner Wrench	Compatible Optic Mounts	Clear Aperture
SM75RR	M75.5 x 0.5	0.16" (4.1 mm)	SPW801^a	LMR75 (LMR75/M)	Ø2.81" (Ø71.4 mm)
SM3RR	SM3 (3.035"-40)	0.10" (2.5 mm)	SPW605 or SPW801^a	Any Internally SM3-Threaded Mount	Ø2.81" (Ø71.4 mm)
SM100RR	M100.75 x 0.5	0.16" (4.1 mm)	N/A	LMR100 (LMR100/M)	Ø3.80" (Ø96.4 mm)
SM4RR	SM4 (4.035"-40)	0.13" (3.3 mm)	N/A	LMR4 (LMR4/M)	Ø3.81" (Ø96.8 mm)

Item #	Thread	Thickness^a	Compatible Spanner Wrench	Compatible Optic Mounts	Clear Aperture
SM05RRC	SM05 (0.535"-40)	0.20" (5.0 mm)	SPW603, SPW603L, or SPW801	Any Internally SM05-Threaded Mount	Ø0.44" (Ø11.0 mm)
SM1RRC	SM1 (1.035"-40)	0.20" (5.0 mm)	SPW606, SPW602, or SPW801	Any Internally SM1-Threaded Mount	Ø0.90" (Ø22.9 mm)
SM2RRC	SM2 (2.035"-40)	0.20" (5.0 mm)	SPW604 or SPW801	Any Internally SM2-Threaded Mount	Ø1.90" (Ø48.3 mm)

Stress-Free Retaining Ring	Clear Aperture	Standard Retaining Ring	Clear Aperture
SM05LTRR	Ø0.32" (Ø8.1 mm)	SM05RR	Ø0.44" (Ø11.0 mm)
SM1LTRR	Ø0.82" (Ø20.8 mm)	SM1RR	Ø0.90" (Ø22.9 mm)
SM2LTRR	Ø1.68" (Ø42.7 mm)	SM2RR	Ø1.90" (Ø48.3 mm)

Item #	Thread	Thickness	Compatible Spanner Wrench	Compatible Optic Mounts
SM05LTRR	SM05 (0.535"-40)	0.15" (3.8 mm)	SPW603, SPW603L, or SPW801	Any Internally SM05-Threaded Mount
SM1LTRR	SM1 (1.035"-40)	0.16" (4.1 mm)	SPW602, SPW606, or SPW801	Any Internally SM1-Threaded Mount
SM2LTRR	SM2 (2.035"-40)	0.18" (4.6 mm)	SPW604 or SPW801	Any Internally SM2-Threaded Mount

Plastic Retaining Ring	Clear Aperture	Standard Retaining Ring	Clear Aperture
SM05PRR	Ø0.44" (Ø11.0 mm)	SM05RR	Ø0.44" (Ø11.0 mm)
SM1PRR	Ø0.80" (Ø20.3 mm)	SM1RR	Ø0.90" (Ø22.9 mm)

Item #	Thread	Thickness	Thread Specs	Compatible Spanner Wrench	Compatible Optic Mounts
SM05PRR	SM05 (0.535"-40)	0.08" (2.0 mm)^a		SPW603, SPW603L, or SPW801	Any Internally SM05-Threaded Mount
SM1PRR	SM1 (1.035"-40)	0.11" (2.8 mm)^a		SPW801	Any Internally SM1-Threaded Mount

Vacuum Specifications
Vacuum Compatibility as Packaged^a	>10^-6 Torr
Material	6061-T6 Aluminum
Preparation and Packaging	Chemically Cleaned and Double Vacuum-Bagged

Item #	Thread	Thickness	Compatible Spanner Wrench	Compatible Optic Mounts	Clear Aperture
SM05RRV	SM05 (0.535"-40)	0.07" (1.7 mm)	SPW603, SPW603L, or SPW801	Any Internally SM05-Threaded Mount	Ø0.44" (Ø11.0 mm)
SM1RRV	SM1 (1.035"-40)	0.08" (2.0 mm)	SPW606, SPW602, or SPW801	Any Internally SM1-Threaded Mount	Ø0.90" (Ø22.9 mm)
SM2RRV	SM2 (2.035"-40)	0.10" (2.5 mm)	SPW604 or SPW801	Any Internally SM2-Threaded Mount	Ø1.90" (Ø48.3 mm)

Vacuum Compatibility Specifications
Vacuum Compatibility as Packaged^a	>10^-9 Torr
Material	303 Stainless Steel
Preparation and Packaging	Chemically Cleaned and Double Vacuum Bagged

Item #	Thread	Thickness	Compatible Spanner Wrench	Compatible Optic Mounts	Clear Aperture
POLARIS-SM05RR	SM05 (0.535"-40)	0.07" (1.7 mm)	SPW603, SPW603L, or SPW801	Any Internally SM05-Threaded Mount	Ø0.43" (Ø10.9 mm)^a
POLARIS-SM1RR	SM1 (1.035"-40)	0.08" (2.0 mm)	SPW606, SPW602, or SPW801	Any Internally SM1-Threaded Mount	Ø0.90" (Ø22.9 mm)
POLARIS-SM2RR	SM2 (2.035"-40)	0.10" (2.5 mm)	SPW604 or SPW801	Any Internally SM2-Threaded Mount	Ø1.90" (Ø48.3 mm)

Item #	Compatible Retaining Rings	Feature	Length
SPW205	SM5RR	Stackable: One End of Spanner Wrench Fits to End of Other Spanner Wrench to Reach Retaining Rings in Longer Lens Tubes	1.00"
SPW206	SM6RR
SPW207	SM7RR
SPW208	SM8RR
SPW209	SM9RR
SPW210	SM10RR
SPW211	SM11RR
SPW603	SM05RR, SM05RRV, SM05RRC, SM05LTRR, SM05PRR, POLARIS-SM05RR
SPW603L	SM05RR, SM05RRV, SM05RRC, SM05LTRR, SM05PRR, POLARIS-SM05RR	Engraved Scale	3.88"
SPW606	SM1RR, SM1RRV, SM1RRC, SM1LTRR, POLARIS-SM1RR	-	1.00"
SPW602	SM1RR, SM1RRV, SM1RRC, SM1LTRR, POLARIS-SM1RR	Engraved Scale	3.88"
SPW607	SM30RR	-	4.35"
SPW608	SM1.5RR	Engraved Scale	3.88"
SPW604	SM2RR, SM2RRV, SM2RRC, SM2LTRR, POLARIS-SM2RR	-	4.35"
SPW605	SM3RR	-	4.35"

Retaining Rings

Retaining Rings Selection Guidea

Features

Threading Specifications

Standard Retaining Rings: Ø5 mm to Ø1/2"

Standard Retaining Rings: Ø13 mm to Ø1"

Standard Retaining Rings: Ø30 mm to Ø1.5"

Standard Retaining Rings: Ø39 mm to Ø2"

Standard Retaining Rings: Ø75 mm to Ø4"

Extra-Thick Retaining Rings

Stress-Free Retaining Rings

Plastic Retaining Rings

Unanodized Aluminum Retaining Rings, Vacuum Compatible

Stainless Steel Retaining Rings, Vacuum Compatible

Spanner Wrenches for Retaining Rings

Retaining Rings Selection Guide^a