This Kinetic Research Group Magazine Release Button is the aluminum mag release button that is standard on the Gen 1-4 Whiskey-3 Chassis. It provides quick, ambidextrous access. It can be fitted to other KRG chassis. Fits: Whiskey-3 Chassis (all gens), Bravo Chassis, X-Ray Chassis (late Gen 1 with W-3 Mag catch, all Gen 2), 180-Alpha (all versions), 180-Xray (Howa inlet)