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 M1913 or Weaver-style accessory rails with Crimson Trace® Secure Locking TechnologyTM. Once locked on, it will not budge under recoil or handling. Instant ActivationTM technology allows you to simply "tap on" and "tap 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 is unintentionally activated.