This is a very compact M4 airsoft gun for CQB battlefields. It's shocking how small this well built all metal gun is. Can use all standard M4 parts, accessories, magazines, etc. This is a Top Tech G&G model, featuring a short unique metal M-Lok rail system, high quality polymer upper and lower receiver, stock, barrel, etc. The barrel has a built-in compensator. This gun is solid! Internally programmable Mosfet unit for 3-round burst and other options. Built to use LiPo batteries out of the box. Compact PDW style stock is rock-solid and adjustable. Front rail is for M-Lok. Includes flip-up front and rear sights. Overall a solid CQB style gun and only 3000 pieces made worldwide!