Airsoft AEGs are "automatic electric airsoft guns" which are powered by batteries and AEG gearboxes. The airsoft gun's gearbox contains motor-driven gears, shims, piston, nozzle, cylinder, cylinder head, tappet plate, switches, low resistance wiring, spring, and other AEG airsoft gun parts. All of these gearbox parts cycle when the airsoft gun trigger is pulled to rapidly compress the AEG spring, move the piston to the rear inside the cylinder, and create a vacuum which draws air into the cylinder. This air is released down the airsoft gun's barrel. AEG's can rapidly fire airsoft BBs in fully automatic, burst, or semi-automatic firing modes. In full auto, the gearbox switches allow the gearbox to keep cycling when the AEG trigger is continuously held back. Learn How AEG Airsoft Guns Work