Specifications Operation: Gas Blowback Firing Modes: Fully-Automatic Blowback, Semi-Automatic Blowback Muzzle Velocity: 360-410 Fps (W/ 0.20G Bbs) Main Outer Body = Fiber Reinforced Polymer Internal Structure = Full Metal Action Housing Inner Barrel = 160Mm Magazine Capacity = 40 Rounds Caliber = 6Mm Airsoft Bbs Gas System = Force Velocity Engine [Fv] Rate Of Fire = 15 ~ 16 Rps** Propellant = Green Gas Only Dimensions = 15 X 7 [38.1 Cm X 17.78 Cm] Weight = 4.7 Lbs. [2.13 Kg]Features Official Heckler & Koch Licensed Product Fiber Reinforced Polymer Body Functional Cocking Handle With Realistic Bolt Movements Metal Picatinny Accessory Rails Retractable Shoulder Stock Flip Up Adjustable Front And Rear Sight Semi And Full Auto Selective Fire Folding Front Grip Trigger Safety Adjustable Hop-Up 45 Days Product Warranty [Us Only] Lifetime Tech Support