Crimson Trace LG-403 Lasergrips Red Laser Sight Grips for Ruger MKII and MKIII Pistols POWERFUL RED LASER: Features a 5mW peak, 620-670nm, Class 3R visible red laser - the brighest 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 FOUR HOURS OF BATTERY LIFE: Powered by two #2032 Batteries (included). This product is eligible for Crimson Traces Free Batteries For Life Program. FITS Ruger MK II and III 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. Instinctive activation and fully adjustable for windage and elevation Manufactured to fit seamlessly with the firearm frame No gunsmithing or frame modifications required for installation Hard Polymer, Rubber overmolded front activation, master on/off switch Class IIIR Laser Product: &lt;5mW power output