For all calibers. Design was thoroughly researched for effectiveness in eliminating muzzle flash. Designed for installation on AKM/AK-74 pattern rifles, as well as Saiga and VEPR rifles(with threaded barrels). COVERS ALL THREADS ON BOTH VEPR AND CENTURY RIFLES. Made of 4140 steel hardened to 38 Rockwell. Side flats at rear allow flash suppressor to be tightened with a wrench. Black oxide finish.