Ø3" Lens Tubes


Ø3" Lens Tubes

  • Directly Accepts Ø3"(Ø75mm) Optics
  • Compatible with All SM3-Threaded Components
  • Stackable Design Enables Construction of Multi-Element Optical Systems


  • Easily Construct Multi-Element Optical Systems
  • Designed for Compatibility with Ø3" (Ø75 mm) Optics
  • Wide Range of SM3-Compatible Optomechanical Components Available

Lens tubes are ideal for creating compact optical subassemblies. The Ø3" 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. These stackable lens tubes ship with one retaining ring. Additional retaining rings can be purchased separately. In addition to the Ø3" lens tubes featured on this page, Thorlabs also offers Ø1/2", Ø1", Ø30 mm, Ø2", and Ø3" versions, each of which is equipped with an SM series thread standard that depends on the tube diameter.

For fine tuning of the first or last lens in a lens tube system, consider using a SM3V10 Adjustable Length Lens Tube.



Ø3" Stackable Lens Tubes


  • SM3-Threaded (3.035"-40) Bore Directly Accepts Ø3" (Ø75 mm) Optics
  • Stackable Design Enables Multi-Element Optical Systems
  • Ideal for Large Optical Assemblies

These stackable Ø3" lens tubes provide a fast and easy means for building compact optical assemblies. Their stackable design and direct interfacing with any SM3-threaded (3.035"-40) components provide flexibility for complex optomechanical assemblies. One SM3RR retaining ring is included with each lens tube.

Item #L1L2Thread Depth
SM3L05 0.65" 0.12" 0.50"
SM3L10 1.15" 0.12" 1.00"
SM3L20 2.15" 0.12" 2.00"






Ø3" Retaining Rings and Spanner Wrenches


  • SM3RR Retaining Rings Secure Ø3" (Ø75 mm) Optics
  • Spanner Wrenches Provide One-Handed Adjustment of SM3RR Retaining Rings
  • SPW801 Adjustable Spanner Wrench can Accommodate Diameters from 0.15" (3.8 mm) to 3.0" (75 mm)

Due to its hollow design, the SPW605 Spanner Wrench enables retaining rings for our SM3 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 SM3RR retaining rings. Please note that the SPW801 wrench can withstand a maximum torque of 80 inch pounds.



Our Mission is to accelerate the advancement of optical technology for precision measurements and their applications from the table tops of research laboratories to standard use in communication and high technology industries. Our aim is to serve our customers. Our hope is to create a place for highly skilled people in an open environment

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