Night vision scopes that mount to front of daytime scope?

[koobs]

Ive been looking into getting myself a new toy but am unsure which type of night vision scope I should be looking for, my intended application is to be able to mount the night vision device to the front of my scopes.

But im not sure what I should be looking for.

what i mean is, do all monocular scopes mount to the front? also ive seen specific terms like night vision scope converter. What is the search term I should be using or type of scope I should be looking for to acheive this?

thanks brothers.