Features - Unique "Crazy Jet" inner barrel creates an air cushion around the BB as it exits the barrel to reduce air resistance for improved performance - High quality brass and aluminum construction - Improved steel pressure plate - High quality metal hop-up adjustment dial - Complete drop-in barrel and hopup unit -  included : I-Key  Maple Leaf 94mm Inner Barrel 6.02 Maple Leaf Pistol Hop Up Adjustment Wheel Maple Leaf Hop Up Chamber Autobot Hop-Up Bucking -Suitable for Marui Hi-Capa 4.3 Series GBB