The 510 Tank electronic cigarette is equipped with a new exclusively Tank atomizer and Tank refillable cartridge which features a tank liquid system. Instead of filling cartridges, you fill the 510-T tank and it keeps a fresh supply of e-Liquid on the 510-T atomizer at all times. You don't have to pull the cartridge out to see if you are running low because the liquid is visible through the translucent 510-T tank cartridge.