The H&K MP5 A Retractable AEG Airsoft Gun contains a dual power, high capacity magazine that allows you to shoot 200-shots without having to reload. The rapid fire capability when the gun is turned to full auto mode comes from the powerful motor that is powered by a 8.4V NiMH battery. The adjustable rear sight allows for precise aiming for the shooter. The retractable stock barrel of the gun lets the person pulling the trigger put the gun in the "mode" that is most comfortable for the environment that he or she is shooting in. Easy adjustment between semi and fully automatic.