a&k m4a1-b electric airsoft gun full auto metal gear fps-400(Airsoft Gun) Features: Manufactured by A&K! Electric Powered (AEG) Velocity (FPS): 400 w/ .20G BB's Can Fire Approxiamately 15 Rounds per Second! High Capacity 300 Round Magazine Full Metal Gearbox with High Torque Electric Motor! High Impact Polymer Body Construction Rock Solid Metal Internals! Adjustable Hop Up System Retractable LE Stock Smart Charger Recommended for ALL AEG Rifles Use High Quality Seamless Rounds, 0.20G or Heavier, to Avoid Misfires and Jams Requires 8.4V 1200mAh Battery to run (Included) Color: Black Length: 34"