SHS Aluminum Air Nozzle 20.2mm for M1A1 Airsoft AEG - AirsoftGoGo Keychain Included Inner O-RIng for better sealing (70 degrees O-Ring) With Grooved Outlet Tighter sealed air nozzle ensures more barrel exit muzzle velocity This Oil Lubricated Air Seal Nozzle increase the air tightness of the cylinder Suitable for M1A1 Thompson Series Airsoft AEG Rifle Version 6 Gearbox Length: 20.2mm