The e-cigarette is used by tobacco cigarette smokers who want an effective way to quit their unhealthy habit. Electronic cigarettes come in a variety of sizes and colours, ranging from ones that are identical in appearance to a real cigarette, to ones that are larger and of a different colouration. Despite the wide range of varieties, they all share a number of common characteristics.

The actual e-cigarette is composed of three parts. The first part is the battery which is usually a re-chargeable lithium ion battery like the one found in mobile phones. Some models have a battery that lights up an orange colour to mimic the appearance of a real cigarette. The second part is the atomizer, which is a metal heating element. It uses the power from the battery to heat up the liquid that is located inside of the third part of an electronic cigarette: the cartridge. The atomizer has been described as the workhorse of the e-cigarette, and it is because of this that it eventually burns out and needs to be replaced. The life of an atomizer depends on the frequency of use and how well it is maintained. Most cartridges are re-fillable and this enables the user to save money over the long term. Some models of electronic cigarette have a fused atomizer and cartridge known as a cartomizer. The main advantage of the cartomizer is that is is much easier to use, and its main drawback is that it does not allow the user to have as much control over the amount of vapour produced.

It is also necessary to have a charger to charge to battery. Furthermore, it is necessary to have some liquid to re-fill the cartridges and cartomizers. It is the liquid that produces the vapour that is inhaled, which gives the sensation of smoking. Cartridges can usually be filled an infinite number of times, but cartomizers are usually only good for about ten re-fills. The liquid is made of propylene glycol, vegetable glycerin and food flavour. It comes in a multitude of flavours.