Ø2" Lens Tubes

• SM2-Threaded (2.035"-40) Bore Accepts Ø2" (Ø50.8 mm) Optics
• Stackable Design Enables Multi-Element Optical Systems
• Compatible with Our 60 mm Cage Assembly Systems

These stackable Ø2" Lens Tubes provide a fast and easy means for building compact optical assemblies. Their stackable design and direct interfacing with all SM2-threaded (2.035"-40) components provide flexibility for complex optomechanical assemblies. One SM2RR Retaining Ring is included with each lens tube.  

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An SM2L15 lens tube used to mount a SOLIS-1A high-powered LED.

• SM2-Threaded (2.035"-40) Bore Accepts Ø2" (Ø50.8 mm) Optics
• Unlike Stackable Lens Tubes, Optics can be Accessed from Both Ends
• Use Lens Tube Couplers to Stack Multiple Lens Tubes
• Allows Coupling of Two Components with External SM2 Threading
• Directly Compatible with Our 60 mm Cage Assembly Systems

Unlike our Ø2" stackable lens tubes featured above, these Internally Threaded Lens Tubes do not feature a lip at one end nor do they have external SM2 threading. Therefore, optics housed inside can be accessed from both ends. To join these lens tubes end-to-end, use an SM2T2 Lens Tube Coupler. Two SM2RR Retaining Rings are included with each lens tube.

• Easy Access to Optics
• Rotatable Slip Shield Protects Optics
• Compatible with SM2-Threaded Components

These stackable Ø2" Lens Tubes with side slots provide 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 SM2RR 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.

The SM2E60 6" Long Extension Tube is designed to enable longer distances between optical components in lens tube systems that utilize lenses with large focal lengths. Although the ends of these extension tubes are threaded to accept our SM2 series stackable lens tubes, they feature thicker walls than our standard lens tubes, which leads to greater rigidity.

• Four Types of Retaining Rings for Securing Ø2" Optics
• Spanner Wrenches Provide One-Handed Adjustment of Retaining Rings
• SPW801 Adjustable Spanner Wrench can Accommodate Diameters from 0.12" (3.0 mm) to 2.89" (73.4 mm)

Thorlabs offers four different kinds of SM2 (2.035"-40) retaining rings. The SM2RR is our standard aluminum retaining ring that ships with our Ø2" lens tubes as well as many other Thorlabs components, and is available individually and in packs of 5.

Additionally, SM2RR Retaining Rings can be swapped out for one of the SM2-threaded retaining rings listed in the table to the right. Please keep in mind that due to the increased thickness of some retaining rings, the maximum optic thickness that can be housed inside our standard SM2-compatible mounts will be diminished in some cases.

There are also two spanner wrench choices that can be used with these retaining rings. The SPW604 Spanner Wrench has a hollow design that enables retaining rings for our SM2 series of lens tubes to be adjusted and installed without obscuring the beam path. The handle is knurled for improved grip. Alternatively, the SPW801 Adjustable Spanner Wrench can also be used to position SM2RR or SM2LTRR retaining rings. Please note that the SPW801 wrench can withstand a maximum torque of 80 inch pounds. We also offer the SPB2 Spanner Bit, which can be used with a standard 1/4" hex driver (sold separately). The SPB2 is included as part of the SPB600 Spanner Wrench Bit Kit.