- M42x1 internal thread with T-2 external thread
- Transition adaptor for all Russian threaded M42x1 to the T-2 M42x0.75 thread.
- Allows 1¼" eyepiece tubes, cameras and the OPFA projection system to be connectable to Russian equipment.
- Fits most Russian telescopes (Intes / TAL / Rubinar u. A.) "Russians adapter"
