Comes with an upgraded maxx mag catch Aluminum alloy receivers SPD front assembly Integrated MOSFET; 8mm ball bearing bushings; Quick change spring system Ambidextrous fire selector Adjustable rotary hop-up 2 position compact carbine stock Non-functional mock bolt plate, plate mechanism, internal catch and catch spring removed for further weight reduction The Alpha SDP is a compact, lightweight, full metal AEG that combines the maneuverability of a pistol with the firepower and capacity of a rifle. Based on the AR design, the Alpha SDP features a futuristic aluminum hand guard with a smooth finish for a comfortable grip. The aluminum receivers feature a stamped KRYTAC logo and accept airsoft M4 style magazines. Additional features include an ambidextrous fire selector and the KRYTAC rotary hop-up system. The KRYTAC rotary hop-up has 15 adjustment settings and a numbered adjustment wheel for a quick reference point to determine how much hop is needed. The battery is stored in the buffer tube of the KRYTAC Compact Carbine stock, which was designed to provide ample room for a wide range of batteries. The external features of the Alpha SDP are engineered for durability and ergonomics, the heart of the performance lies within the gearbox.