By Leigh Schaller

Lithium Battery

Rechargeable, and often designed to look like the white part of a normal cigarette.

LED Indicator

A small, usually red, light which glows as the smoker takes a drag.

Sensor & Microprocessor

An airflow sensor detects when the smoker is inhaling and activates the microprocessor, which in turn activates the atomiser.

Related: Your E-cigarette Exclusive

Wick Or Metal Sponge

This delivers a small amount 
of liquid from the ingredients 
cartridge to the coil.

Atomiser

This consists of a sponge, surrounded by a coil, inside a chamber. When activated, the coil heats up and vaporises the liquid, which is inhaled, delivering a single nicotine hit. The atomiser and ingredients cartridge could be two separate units or a single unit.

Ingredients Cartridge

The liquid inside consists of a mixture of propylene glycol, nicotine and water. The user has the option of choosing a solution that contains flavouring. A single cartridge contains enough fuel to last for around 200 puffs, depending on the model.

Related: E-Cigarettes Won’t Help You Quit Smoking

Mouthpiece

Depending on the  model, the mouthpiece can either be part of the cartridge or detachable.