The Saker 556K is designed for 5.56 NATO semi-auto and full-auto firearms. In addition to its performance, the Saker ASR's design allows for maximum user adaptability and convenience. ASR(TM) (Active Spring Retention) Mount technology facilitates attachment via a variety of different flash hiders, muzzle brakes, and direct thread mounts. The Saker 556K is a .223 REM/ 5.56 NATO dedicated suppressor. Best AR Suppressor Best 5.56 Nato suppressor