MWS ZET Inspired Gas Blowback Rifle of the Improved HK 416A5 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 11-in Outer Barrel with Quad Picatinny Rail Interface Handguard 6 Position Adjustable Buttstock with borrowed G28 Stock Design Integrated Foldable Front Iron Sight with Foldable Rear Sight Storage Space in Pistol Grip Ambidextrous Fire Controls accessible for Right- and Left-Handed Shooters 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.