The DS-124 Defender Series Accu-Grips Laser Sight by Crimson Trace fits Smith & Wesson J-Frame (Round Butt) and Taurus Small Frame Revolvers. The Defender Series sets a new standard in laser sighting systems by providing cutting edge design, superior technology, and an affordable price tag. The DS-124 features Beam Lock Adjustments so that the user can easily adjust laser sighting for both windage and elevation, and the unit is pre-sighted at the factory at 50 ft. The Top N-Gage Activation Button provide a large, easy-to-find, bright red activation button, which emits a powerful (5mW peak, 620-670nm, Class 3R) red aiming laser..