Vehicle audio includes mobile audio, car audio, 12-volt (sometimes other voltages such as 6-volts for pre-1950s vintage cars and 24-volt for civilianized military vehicles or heavy-duty commercial civilian trucks or for light vehicles such as golf carts that use 24-volt electric motors) audio and other terms are used to describe sound systems fitted to an automobile or other vehicle.The focus of this article is the use in automobiles (hence car radio or car stereo), though the term can be used referring to similar systems fitted to marine and aviation craft, motorcycles, or heavy industrial equipment.