A T2 thread, also written T-2, has a diameter of 42mm and a thread pitch of 0.75mm. It is also sometimes written as M42x0.75.
The low pitch distinguishes it from other M42 threads.
Omegon
adapter ring M48-T2 0mm
$ 17.90
ready for shipping in 24
h
Omegon
Adapter Visual T male to 1.25” female with set screw
$ 34.90
ready for shipping in 24
h