Very effective AKM/AK47/AK74 multi chamber muzzle brake that virtually eliminates all muzzle rise.Fits AK74 M24mm X 1.5 RH barrels with detent. Includes internal thread adapter for AKM/AK47 M14mm X 1 LH threaded barrels with detent.Designed for 7.62X39, 5.45X39, 5.56X45 (.223) calibers.Multiple chambers and ports on the top and sides directs expanding gasses upwards reducing muzzle rise.There are no ports on the bottom of the muzzle brake to reduce dust signature when shooting prone.Length: 3.3Weight: 6.9 oz. (with AKM/AK47 M14 X 1 thread adapter)US PAT. D807,461