
Lens tubes are ideal for creating compact optical subassemblies. The Ø1" lens tubes sold here can be used to house one or several optical elements. Optics are separated and secured by retaining rings that are positioned at the desired depth within the lens tube using a spanner wrench. Depending on the item purchased, one or two retaining rings will be included (see below for details). Additional retaining rings can be purchased separately. In addition to the Ø1" lens tubes featured on this page, Thorlabs also offers Ø1/2", Ø30 mm, Ø2", and Ø3" versions, each of which is equipped with an SM series thread standard that depends on the tube diameter.

| Ø1" Shortcuts |
|---|
| Lens Tube Couplers SM Thread Adapters Lens Tube Mounts End Caps Kinematic Mounts Fixed Lens Mounts Rotational Mounts Translation Mounts |
| Lens Tube Compatible Products | |||||||
|---|---|---|---|---|---|---|---|
| Thread Adapters | Terminated Fiber Adapters | Collimation Package Adapters | LED and LD Mounts | Aspheric Lens Mounts | Irises, Apertures, and Shutters | Alignment Tools | |
Thorlabs' lens tubes utilize a series of non-standard threadings. Threading specifications are given below for our SM threadings utilized in our lens tube and cage system components so that you can machine mating components to suit your application. For threading specifications other than what is 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" |
| 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, M30.5x0.5 | Internal Thread, M30.5x0.5 | ||
| 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 |
| 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" |
These stackable Ø1" lens tubes provide a fast and easy means for building compact optical assemblies. Their stackable design and direct interfacing with any SM1-threaded (1.035"-40) components provide flexibility for complex optomechanical assemblies. One SM1RR retaining ring is included with each lens tube.
| Item # | L1 | L2 | Thread Depth |
|---|---|---|---|
| SM1L03 | 0.45" | 0.12" | 0.3" |
| SM1L05 | 0.65" | 0.12" | 0.5" |
| SM1L10 | 1.15" | 0.12" | 1.0" |
| SM1L20 | 2.15" | 0.12" | 2.0" |
| SM1L30 | 3.15" | 0.12" | 3.0" |
| SM1L40 | 4.15" | 0.12" | 4.0" |

| Alternatives | Ø1/2", Ø30 mm, Ø2", and Ø3" Stackable Lens Tubes | Ø2" Lens Tube Extensions | Ø2" Lens Tubes with Side Access Ports |
|---|
Part Number |
Description |
Price |
Availability |
|---|---|---|---|
SM1L03 |
SM1 Lens Tube, 0.3" Thread Depth, One Retaining Ring Included |
$12.16 |
Today |
SM1L05 |
SM1 Lens Tube, 0.5" Thread Depth, One Retaining Ring Included |
$12.59 |
Today |
SM1L10 |
SM1 Lens Tube, 1" Thread Depth, One Retaining Ring Included |
$14.25 |
Today |
SM1L20 |
SM1 Lens Tube, 2" Thread Depth, One Retaining Ring Included |
$16.50 |
Today |
SM1L30 |
SM1 Lens Tube, 3" Thread Depth, One Retaining Ring Included |
$25.75 |
Today |
SM1L40 |
SM1 Lens Tube, 4" Thread Depth, One Retaining Ring Included |
$44.00 |
Today |

Unlike our Ø1" stackable lens tubes featured above, these internally threaded lens tubes do not feature a lip at one end nor do they have external SM1 threading. Therefore, optics housed inside can be accessed from both ends. To join these lens tubes end-to-end, use an SM1T2 Lens Tube Coupler. Two SM1RR retaining rings are included with each lens tube.
| Alternatives | Ø1/2" and Ø2" Lens Tubes Without External Threads | ||
|---|---|---|---|
Part Number |
Description |
Price |
Availability |
|---|---|---|---|
SM1M05 |
Customer Inspired!SM1 Lens Tube Without External Threads, 1/2" Long, Two Retaining Rings Included |
$12.00 |
3-5 Days |
SM1M10 |
Customer Inspired!SM1 Lens Tube Without External Threads, 1" Long, Two Retaining Rings Included |
$13.25 |
Today |
SM1M20 |
Customer Inspired!SM1 Lens Tube Without External Threads, 2" Long, Two Retaining Rings Included |
$15.50 |
Today |
SM1M30 |
Customer Inspired!SM1 Lens Tube Without External Threads, 3" Long, Two Retaining Rings Included |
$16.75 |
Today |

These Lens Tube Spacers are designed to connect two components with internal SM1 threads at a fixed distance. They are unthreaded and have a clear aperture of Ø0.95".
Please note that due to the fixed thread depth, the orientation of the attached components will be arbitrary. For full control over the component orientation, Thorlabs offers the SM1T2 externally threaded coupler with adjustable locking rings.
Part Number |
Description |
Price |
Availability |
|---|---|---|---|
SM1S10 |
Customer Inspired!SM1 Lens Tube Spacer, 1" Long |
$12.00 |
Today |
SM1S20 |
Customer Inspired!SM1 Lens Tube Spacer, 2" Long |
$14.00 |
Today |
SM1S30 |
Customer Inspired!SM1 Lens Tube Spacer, 3" Long |
$20.00 |
Today |
Easy Access to Optics
Rotatable Slip Shield Protects Optics
Compatible with SM1-Threaded ComponentsThis stackable Ø1" lens tube with side slots provides a fast and easy means for building complex optical assemblies and adjusting the optics without disassembling the setup. Several optics can be inserted into a single tube using multiple SM1RR retaining rings. Simply thread the first retaining ring to the desired depth, add the optic, and then use a second retaining ring to secure the optic. Optics can be manually adjusted via the side slots without the use of a spanner wrench. The rotatable slip shield included with the lens tube fits over the lens tube slots to prevent unwanted light from entering the system and to keep the optical setup free from debris. Two retaining rings and one black plastic dust cover are included with each lens tube.
| Alternatives | Ø1/2" and Ø2" Slotted Lens Tubes | |
|---|---|---|
Part Number |
Description |
Price |
Availability |
|---|---|---|---|
SM1L30C |
SM1 Slotted Lens Tube, 3" Thread Depth, 2 Retaining Rings Included |
$65.00 |
Today |

The SM1E60 6" Long Extension Tube is designed to enable longer distances between optical components in lens tube systems that utilize lenses with large focal lengths. These tubes feature thicker walls than our standard lens tubes, which leads to greater rigidity. In addition, the ends of these extension tubes are threaded to accept our SM1 series stackable lens tubes.
| Alternatives | Ø2" Extension Tubes | ||
|---|---|---|---|
Part Number |
Description |
Price |
Availability |
|---|---|---|---|
SM1E60 |
SM1 Series Extension Tube, 6" |
$44.00 |
Today |
Thorlabs offers three different kinds of SM1 retaining rings. The SM1RR is our standard retaining ring that ships with our Ø1" lens tubes as well as many other Thorlabs components. If desirable, the SM1RR can be swapped out for am SM1LTRR or an SM1PRR. The SM1LTRR is a stressless retaining ring that is equipped with a Buna-N O-ring to provide a light-tight seal around the optical component while the SM1PRR is a plastic retaining ring that provides increased strength due to its increased thickness [0.11" (2.8 mm) compared to 0.08" (2 mm) for our other Ø1" retaining rings]. Please keep in mind that due to the increased thickness of the SM1PRR retaining ring, the maximum optic thickness that can be housed inside our standard SM1-compatible mounts will be diminished in some cases. Thorlabs also offers two spanner wrench choices: the 1" long SP606 and the 3.87" long SPW602, which can be used with the SM1RR and SM1LTRR retaining rings, and the SPW801, which can be used with all three types of SM1 retaining rings.
| Alternatives | Ø1/2", Ø2", and Ø3" Fixed Diameter Spanner Wrenches | Ø1/2", Ø2", and Ø3" Retaining Rings | |
|---|---|---|---|
Part Number |
Description |
Price |
Availability |
|---|---|---|---|
SM1RR |
SM1 Retaining Ring for Ø1" Lens Tubes and Mounts |
$4.50 |
Today |
SM1LTRR |
SM1 Series Stress-Free Retaining Ring |
$21.40 |
Today |
SM1PRR |
Customer Inspired!SM1 Plastic Retaining Ring for Ø1" Lens Tubes and Mounts |
$5.30 |
Today |
SPW606 |
Customer Inspired!SM1 Spanner Wrench, Length = 1" |
$26.00 |
Today |
SPW602 |
SM1 Spanner Wrench, Graduated, Length = 3.88" |
$26.00 |
Today |
SPW801 |
Adjustable Spanner Wrench |
$95.90 |
Today |
SPW102 |
Adjustable Spanner Wrench, Replacement Blade Set |
$27.90 |
Today |