I have an Original ND3 that I use for night varmint and hog hunting.These things work great,but you need to carry extra batteries for an all nighter.
Mine will start to fade out when the temp drops down in the 20's,the Sub Zero is supposed to solve that problem.
The unit comes with a 1" scope mount and 2 other non gun mounts.If you need a 30mm scope mount,they're around $50,I know-I bought one.
It is very easy to see at night,and the beam can be adjusted in size.I have used mine out to 200 yards,but it shines further with the beam turned down smaller.It works really good with an illuminated (red) reticle scope.
The scope mount also has adjustments for windage & elevation,so you can center the laser in your scope.
Other hunters can also see the light thru their scopes,so more than 1 hunter can use your ND3 at the same time.
Hope this answers some of your questions. THB
Here's the ND3 on my Savage 12 FLVSS - 223