Personal Vapour Devices (from here on just referred to as PVDs) consist of 3 components: a battery, an atomizer and a liquid filled cartridge. When a person takes a drag the atomizer and the light on the tip (if equiped) is powered on by the battery. The atomizer heats the air drawn into the PVD to a high enough temperature that it vaporizes the liquid solution in the replaceable/refillable cartridge. The vapor is then inhaled into the mouth and lungs fully simulating the "smoking" experience and satisfying the craving smokers seek.
The simulated "smoke" is actually just water vapor that evaporates in a few seconds and leaves no lingering odor.