NcSTAR Compact Pistol Blue Laser with Strobe And KeyMod UnderMount - BlackMounts onto most Weaver Picatinny MIL STD 1913 Pistol accessory spec rails. Fits full size and compact framed pistols with 1. 7" 2. 0" accessory rails. Fully adjustable for windage and elevation. Blue Laser: 450nm, Max output less than 5mw, Class IIIa Laser. Button on each side of Laser Body allows the user to turn laser On Off. Holding the button down while the laser is On, turns the Strobe feature On Off. The laser features our Patented KEYMOD