This is a 30 caliber (7.62x39mm) muzzle device in the awesome AK-74 pattern. Some still consider this to be the pinnacle of muzzle brakes for the AK. It is threaded for 24mm modern Kalashnikovs. Made by Arsenal and U.S. manufactured so you know this is a quality component for your AK and it works as good as it looks. It would be very difficult to find a better value in a muzzle brake for your AK rifle.