The KeyMicro Brake is a short, lightweight single port muzzle brake suited for a variety of platforms. Designed for use with Dead Air's KeyMicro Adapter, it functions as a minimalist brake on its own. Pair them together for the ultimate mounting platform. This is the same technology found in their industry-best KeyMo system. The KeyMicro muzzle devices are also compatible with Dead Air's KeyMo Adapter.KeyMicro muzzle devices feature a 9mm Bore.