Visual Mill post for Tormach

Hi

This is my first post here :wave:and I have a quick questions, I am setting up Visual Mill to post for Tormach, but it is giving me 3 options:

Tormach MM
Tormach INCH
Tormach

I am not going to use Tormach MM, but does anybody know what the difference between the Tormach and the Tormach INCH is ?

Thank you