The Echo 1 Red Star AK Tactical Flash Hider CCW is a basic black custom AEG style muzzle brake for your airsoft gun. Fits on 14mm negative CCW threaded barrels. Fits directly on AK-47 and non-AK airsoft guns. Black metal construction.*Includes 21mm adapter to fit directly on E&L AK airsoft guns. This is a great option to give your E&L rifle that custom look. Fits on all Gens of E&L.Fits on all AEGs that are CCW (99% of them).