Requires at least 1 3/4" of rail space Requires only 1.75-inches of rail space Quick attach/detach system permits installation in the field Easily programmable for steady or high-vis pulsed beam Adaptable for long gun use with momentary activation system (not included) Automatic time-out feature prevents accidental battery drain Class 3R Laser Product (Does not exceed Class IIIA emission limits), &lt;5mW power output