This is a great green laser on a rifle or carbine, but not so much for compact pistols as it is quite large compared to smaller lasers.
The upside is the battery is a common 123 size, and that also allows it to run for a very long time.
The attached rail is very sturdy. Mounting a stubby forward handle to this laser is a good option on a AR or carbine, and you can operate the laser with your thumb. It is very sturdy, and holds zero fine. I have mounted it on my Mini 30, and it handles the 7.62x39 recoil just fine. (And the Mini 30 action is a recoil monster that has killed a few optics and lights in the past.)
I have also used it on a CX4, and it works very well. You can clearly see the laser dot out to 100 yards in most light conditions, even bright sunlight if the target is in shade at all. In lower light, or at night, this laser can be seen in a an optic at 100's of yards easy, even with zero magnification.
My personal favorite is to have a stubby vertical grip mounted to the unit, so you can control the laser with your thumb, and it becomes part of the grip.
Pros: Provides another rail mount.
Cons: Is not compact.
This review was written in the old system and had content requirements that are different than reviews written today.