Crimson Trace DS-124 Defender Series Accu-Grips Red Laser Sight Grips for Smith & Wesson J-Frame and Taurus Small Frame Revolvers POWERFUL RED LASER: Features a 5mW peak, 620-670nm, Class 3R visible red laser - the brighest beam allowed by law. N-GAGE ACTIVATION: Tap-On / Tap-Off Top Button Controls for immediate laser activation. OVER TWO HOURS OF BATTERY LIFE: Powered by two #2032 Batteries (included). FITS Smith & Wesson J-Frame Round Butt and Taurus models 17*, 85, 94, 327 six-shot, 605, 650, 651, 731, 850, 905 and 941. Does not fit Public Defender. Does not fit Polymer frame models. *Except Tracker. EASY INSTALLATION: User installed- no gunsmithing required. Factory sighted at 50 feet, but is fully user adjustable for Windage and Elevation with provided tool.