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.

TS Optics
Diagonal prism T2 90°
$ 101.00
ready for shipping in 3-7
days

Baader
Amici prism 90° T2 BBHS®
$ 332.00
ready for shipping in 1-2
weeks

Baader
BBHS® T2 mirror star diagonal
( 5 / 5 )
$ 310.00
ready for shipping in 24
h

Baader
Zenith prism T-2/90° 32mm prism
$ 124.00
ready for shipping in 1-2
weeks

Baader
Diagonal mirror Maxbright Universal 90° T2
$ 250.00
Product can be shipped as of 01.02.2026

Baader
90°, T2 star diagonal with 35mm of free aperture
$ 274.00
Product can be shipped as of 06.07.2025