Crimson Trace LG-443G Laserguard Green Laser Sight for Glock 42 and 43 Pistols 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. This is the feature that sets Crimson Trace apart from the rest. OVER TWO HOURS OF BATTERY LIFE: Powered by one 1/3N Battery (included). This product is eligible for Crimson Traces Free Batteries For Life Program. FITS: Glock 42, 43 EASY INSTALLATION: User installed- no gunsmithing required. Factory sighted at 50 feet, but is fully user adjustable for Windage and Elevation with provided tool. This model features a master ON/OFF switch for completely powering down the unit.