Steel front outer barrel and flash hider, magnesium receiver set, 6.04mm precision barrel, M100 spring, metal hop up, reinforce gear box, steel gear set, Tactical sling attachment, 450 rounds hi-cap magazine. Very heavy and rigid, and comes with red practice barrel cap as seen on real steel M4's. Battery is not included. Super fast motor means that this rifle delivers a high rate of fire with unnoticeable trigger delay. Excellent value for money! Large fix stock can holds large battery - 8.4v2000mah.