Crimson Trace LG-639G Lasergrips Green Laser Sight Grips. The Crimson Trace LG-639G Green Lasergrips for GLOCK Gen3, Gen4 & Gen5 Compact are a rear-activated green laser sight for GLOCK Compact pistols (Third Generation 19, 23, 25, 32, 38, Gen4 19, 23, 32, and Gen5 19). Featuring Crimson Trace’s famed instinctive activation, which allows the laser to be activated with a normal firing grip, the LG-639G includes a Master On/Off Switch for completely powering down the unit. User-installed in moments by attaching securely to the gun frame, this laser sight is fully adjustable for windage and elevation. It provides 2 hours of run time with (4) included 2016 lithium batteries. Ultra Bright Green Laser: Features a 5mW peak, 515-532nm, Class 3R visible green laser, the brightest beam allowed by law Instinctive Activation: Front activation button engages the laser immediately when the firearm is held in a normal firing grip Over Two Hours of Battery Life: Powered by four #2016 Batteries; Eligible for Crimson Traces Free Batteries For Life Program Fits Glock Third Generation 19, 23, 25, 32, 38. GEN4 19, 23, 32. GEN5 19 User installed- no gunsmithing required; Factory sighted at 50 feet, but is fully user adjustable for Windage and Elevation with provided tool. WARNING: This product may contain chemicals known to the State of California to cause cancer or reproductive harm. Every product is packaged carefully for safe travel.