Steel adapter allows you to install muzzle brakes and flash hiders on an AK -47 tactical rifle with an un-threaded barrel. No machining necessary. With three machined set screws it can be secured to barrel easily. Adapter features 14mm-1.0 (LH) left hand threads for 7.62x39 caliber AK-47 and SKS rifles. Outside diameter of the barrel must be .54 or THINNER to fit into the adapter. Adapter hole for the bullet is only .343"**Back Order Only-2-3 weeks**