Atomizer is the heating element responsible for vaporizing the liquid, and generally consists of a simple filament and wicking metal mesh to draw the liquid in. It is positioned in the center of the three components that make up the entire electronic cigarette cylinder, as the cartridge attaches to one end, and the power unit to the other. The atomizer's filament tends to lose efficiency over time due to a buildup of sediment, or "burns out" entirely, requiring replacement. This creates one of the primary recurring expenses associated with electronic cigarettes.