Cartridges are accessories for electronic cigarettes that hold the juice that is heated by the atomizer. These are replacable items and work in conjunction with a battery and an atty. There are various types of carts depending on the type of electronic cigarette kit that one owns. For the 510 T and Ego T kits, the cartridges are a tank style that need to be pierced by the T atomizers for the liquid to be heated and vaped. For standard kits, such as a standard 510 or Ego, the carts are wool carts and can come in various colours and shapes.