Constant red laser beam is the highest power output laser commercially available. The built-in extra rail lets you keep all your rail space. It’s as small as a matchbox, requiring only 1.75" of rail space so it’s perfect for use on medium and full-size pistols, carbines, rifles, shotguns and more. So rugged, it will survive multiple drops on concrete. LaserMax even baked it to 350ºF and it still worked. Adjustable windage and elevation setting for precise alignment. Maintains alignment through battery changes. Uses two 357 batteries.