Crimson Trace LG-489G Laserguard Green Laser Sight for Smith & Wesson M&P Shield 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: Smith & Wesson M&P Shield and M&P Shield M2.0 9MM and .40 S&W. Does not fit models with integrated laser. EASY INSTALLATION: User installed- no gunsmithing required. Factory sighted at 50 feet, but is fully user adjustable for Windage and Elevation with provided tool. WARRANTY: 3 Year Manufacturer Warranty and FREE Batteries for Life