HiLight Tactical LED Flashlight and Green Laser Combo for Pistols (W/Green Laser) LED Flashlight: high quality CREE XM-L2 LED with 400 lumen output strobe powered by 2x CR2 battery (included) Mount: clamp mounting system fits all Weaver and Picatinny rails, and fits Glock 17, 19 or similar sizes of pistols. It requires 1.5" clear space in front of trigger guard Green Laser: &lt; 5 mW, Class IIIA Green Laser Sight meets US law requirements (5mW peak, 532nm, Class 3R). Operation: push button switch allows the user to instantly activate or deactivate the laser, optional pressure switch included. Battery: 2x CR2 Lithium batteries (included). After batteries installed, it is necessary to push a small nab upward so battery cover can be firmly locked.