These devices have a battery powered heating element and tank that contains a liquid solution made by combining nicotine, vegetable glycol or propylene glycol and flavorings. The gadget that can be bought in a variety of shapes and sizes usually resembles a pen or a regular cigarette, and it works like a vaporizer. The liquid used in e-cigs is commonly made of propylene glycol, glycerin, distilled water, artificial (fake) flavors and optionally nicotine. It often tastes like tobacco, fruit, mint/menthol or sweets.