Update to a previous review:
When I first received the item the (expensive) included battery had died. They cost approximately $16 to replace, which erodes most of the savings on this item. After moderate use at the shooting range while mounted to my 9mm pistol, the laser no longer works 3 months later.
This may be more suitable for airsoft or Nerf guns than actual firearms.
Never trust an NCStar product on a firearm larger than a 22lr.