The SP ATC (Advanced Tactical Compensator) was engineered using CFD analysis software to design the best compensator available. SP's unique side port design minimizes recoil as well as muzzle rise. Instead of allowing the first port to do the majority of the work our proprietary front facing ports spread out the load minimizing felt recoil and reducing muzzle flash. Instead of using a crush washer, included is a knurled jam nut to make installation and removal for cleaning a breeze. No special gunsmithing is required. The SP ATC is available in either 1/2-28 threads for.223/5.56 or 5/8-24 for up to 30 cal. The ATC-AR brake is designed to be used on barrels with muzzles no larger than .750 (most common gas block size).