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. Product Specifications Product Type: Rail Master Material: Polymer Attachment: Accessory Rail Activation Location: Switch Activation Sighting: Factory Sighted at 50' Battery Type: One 1/3N Lithium Battery Laser Battery Life: Over Four Hours Laser Output: 5mW Red Laser Activation Mode: Instant Activation Laser Visibility: Approx .5 Inch Diameter at 50 Feet Wrench Size: 0.05 Finish: Polymer Housing Installation: User Installed Warranty: Three Year Full Warranty Color: Black Dot Size: Approx. 0.50" at 50'