An electronic cigarette is made up of three separate sections (the battery, the atomizer and the cartridge/mouthpiece) that are assembled together. They typically form a device that looks like a conventional tobacco cigarette although can sometimes be bought in a completely different style. Whatever the aesthetic, all electronic cigarettes have the same primary components and work in the same way. Electronic cigarettes have the advantage of being free of the 4,000 chemicals included in a tobacco cigarette.