The P.E.S.T. is a “centrifugal” launcher using a rotor powered by a DC motor to accelerate plastic BBs. It has a 50 round magazine and 3 fire modes: semi-auto, 3 round burst, and full-auto. Fire is not instantaneous because it takes 0.75 seconds for the rotor to spin up. If you follow this “read” link you’ll find a detailed description of the device. Photos can be found here.