Includes the Brownells Enhanced Safety Button and the other parts in the safety system that get worn, dinged up, or lost. Replace everything at the same time to ensure smooth, positive, reliable operation of this critical component. Safety button screw also sold separately, so you dont have to buy a whole new kit if the screw gets damaged during installation. Mfg: Brownells SPECS: Kit includes enhanced safety button, button screw, detent plate, detent ball, detent spring, and installation instructions. Fits Mossberg 500/590/835 shotguns.