You been living under a rock? LOL
Anyways, don't get the A, that's the dated one.
Get the G. "HS403G" Those are compatible with T1/H1 mounts, where as the A is not, as far as I know. Also the battery compartment is above, not under, very similar to the T1.
- Canada ammo has a good price, 1/3 mount too, think it's like $239 +tax shipped
I'm waiting for their EoTech look alike.