Features: Multi-port design reduces felt recoil up to 76% (depending on caliber) Top and side ports direct gases to reduce muzzle rise Closed bottom design reduces dust signature during firing Rugged all-steel construction Multi-caliber design fits most rifle barrels .30 caliber or smaller with a 5/8"-24TPI or 1/2"-28TPI threaded muzzle. (Barrel shoulder must be at least .700" to install)