Enclosed in a roughed polymer shell, the NUPROL series of Single Drum Magazines hold up to 1200 rounds (AK series also have a 3500R option). Powered by three AAA batteries - keep the BBs coming by holding the button to the front of the drum to maintain tension in the drum. Alternatively, purchase the "SC" (Sound Controlled) version that maintains tension as the shots are fired.Requires (x3) AAA