The Strike Industries AR Modular Bolt Catch (MBC) offers a quick and simple way to configure your button preference to one of four (4) included options. No need to remove the bolt catch base, as we know the roll pins are always a fun time, if you want to change the button. Using the provided hex key, remove the set screw to slide the current bolt catch button off the base and then slide the button on you want. Secure using the correct provided set screw and you are good to go. The SI AR MBC comes with included Standard, Oversized, Left Extended and Right Extended buttons so you always have the modularity to swap at home or at the range. Each bolt catch button is textured for positive feel and manipulation of your AR for enhanced ergonomic control. The provided bolt catch buttons are made from lightweight polymer paired with a heat treated steel bolt catch base. Included as well is a bolt catch roll pin and spring to make this package as complete as possible to give you everything out of the package for a drop-in installation. The Strike Industries AR Modular Bolt Catch gives you the ability meet various setups to your personal liking or specific mission in this complete assembly.