The Action Army Custom Outer Barrel is designed to be used on the AAC 21 and KJW M700 Airsoft Sniper Rifles. The fluted barrel design gives the gun a more unique and streamline finish. The external coating offers protection to the outer barrel from heavy scratches as well as rust. Being constructed out of aluminum, the overall weight is lighter but stronger. The front of the barrel contains a 14mm counter clock wise thread for mounting barrel extensions for those that choose to run a longer inner barrel. This custom outer is specifically designed for the AAC 21/ KJW M700 and may work with other airsoft guns but cannot be guaranteed. Designed for KJW M700 Gas Airsoft Sniper and Tanaka M700 Gas Airsoft Sniper Package include: One (1) Custom Outer Barrel