Airsoft rifles use potential energy stored in a spring to launch a pellet down the barrel of the airsoft rifle. This is typically achieved by pulling back the bolt, which in turn compresses the spring and makes it ready to fire. In contrast, electric airsoft guns, or AEG, normally utilizes a rechargeable battery to power the electric motor that works the internal assembly to shoot the pellets. A least three gears, metal or plastic, are mounted within a gearbox that the motor powers.