MWS ZET Inspired Gas Blowback Rifle of the Legacy HK 416D Rifle Heckler & Koch x CYMA CGS Collab, Umarex (Elite Force) License Member of the Lightning Series - Aluminum Housing with Aluminum Bolt Carrier w/ Polymer Buffer for 18rps Cyclic Rate of Fire, Fire Controls and Components Reinforced with Steel 10-in Outer Barrel with Quad Picatinny Rail Interface Handguard 6 Position Adjustable Buttstock with E1 Rear Stock Removable Fixed Iron Sight with Diopter Drum Rear Sight Storage Space in E1 Stock and Pistol Grip Quick Release Hop Up Chamber - Does not Require Removal of Barrel Nut Adjustable Hop with Flat Head Screwdriver Crisp Trigger with Short Wall Break Steel Fire Control and Components w/ Aluminum Exterior Construct Black Finish This product is only compatible with gas designed specifically for Airsoft guns. Do not use lighter fluid or butane gas, as that will cause permanent damage.