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.

ZWO
Camera ASI 2600 MC Pro Color
RRP:
$ 3,160.00
Our price:
$ 2,687.00
ready for shipping in 24
h

ZWO
Camera ASI 2600 MM Pro Mono
RRP:
$ 4,070.00
Our price:
$ 3,457.00
ready for shipping in 24
h

ZWO
Camera ASI 174 MM Mono
RRP:
$ 920.00
Our price:
$ 779.00
ready for shipping in 3-5
weeks

QHY
Camera 183C Color
$ 970.00
ready for shipping in 1-2
weeks

ZWO
Camera ASI 462 MM Mono
RRP:
$ 436.00
Our price:
$ 371.00
ready for shipping in 24
h

Starlight Xpress
Camera Trius PRO-674C Color
$ 2,510.00
ready for shipping in 1-2
weeks

Starlight Xpress
Camera Trius PRO-674 Mono
$ 2,510.00
ready for shipping in 1-2
weeks

Starlight Xpress
Camera Trius PRO-825 Mono
$ 1,850.00
ready for shipping in 24
h

Starlight Xpress
Camera Trius PRO-825C Color
$ 1,850.00
ready for shipping in 1-2
weeks

Starlight Xpress
Camera Trius PRO-694C Color
$ 3,140.00
ready for shipping in 24
h

Explore Scientific
Camera Deep Sky Astro 26MP
$ 1,820.00
ready for shipping in 1-2
weeks

QHY
Camera 183M Mono
$ 1,360.00
ready for shipping in 1-2
weeks

QHY
Camera 294M Pro Mono
$ 1,760.00
ready for shipping in 1-2
weeks

Starlight Xpress
Camera Trius PRO-825 Mono, Combi Set
RRP:
$ 2,710.00
Our price:
$ 2,500.00
ready for shipping in 1-2
weeks

QHY
Camera 163 cool Mono
$ 1,580.00
ready for shipping in 1-2
weeks