One of a series designed by a Bushmaster employee - features 3 gas ports, a machine turned ribbed design, and a closed bottom. It is bored to function as a Flash Suppressor, but also effectively controls muzzle rise in rapid fire. Quality gunsteel - manganese phosphate finished - 2 3/16" overall length - threaded 1/2" x 28 T.p.I. (threads per inch) for 5.56mm/.223 Rem. caliber barrels. Install using a 3/4" open end wrench and a crush washer or peel washer.