The Crimson Trace Rail Master universal laser sight attaches to nearly any picatinny or weaver-style rail with no modifications. The four fit inserts allow for use with all the most common pistol equipped rails with a minimum of 1-1/16" from the recoil lug. The Rail Master features a 5mW red or green laser with ambidextrous instant tap on/off activation and auto shut off after 5 minutes of inactivity to conserve battery life. The quality that comes with the Crimson Trace name provides the assurance that the Rail Master will perform flawlessly in any self-defense situation. Covered by a 3-year full factory warranty. Crimson Trace also extends one free set of batteries each year for life when you register your Crimson Trace product on the manufacturers website. Notes:Batteries includedIncludes four fit inserts to accommodate most picatinny or weaver-style rails.Will fit pistol equipped rails with a minimum of 1-1/16" from the recoil lugFeatures auto shut-off after 5 minutes ...