The CMR-201 Rail Master® is a powerful and versatile laser sight designed to fit rail-equipped pistols, rifles and shotguns. The Rail Master locks onto Picatinny M1919 or Weaver-style accessory rails with Crimson Trace's Secure-Lock Technology™. Once locked on, it will not move under recoil or handling. The universal design of the Rail Master offers quick Instant Activation™ by simply "tapping on" and "tapping off" from either side with the ambidextrous activation control tabs. Additionally, the CMR-201 features a 5 minute auto-shut off feature that will power down the unit to conserve battery life if the laser sight is unintentionally activated. Versatile and flexible, the CMR-201 laser sight includes four (4) different inserts to adapt to various firearm platforms. The unit features a powerful 5mW red laser that will run for over four (4) hours on a single 1/3N Lithium battery. Rail Master is factory sighted at 50', but is fully user adjustable for windage and elevation. Fits pistols, rifles, and shotguns with M1913 Picatinny or Weaver-style Accessory Rail.