This e-cigarette accessory offers a warm, smooth vaping experience. It uses a bottom coil system, and features a smoothly contoured metal mouthpiece, a pyrex tube, and it is rebuildable! The Kanger Protank system delivers large amounts of vapor with its generous air flow and professional design. This is one of Kanger’s premiere systems, and it is a must for any expert vapors. It has 510 threading, comes with 2 heads, a base, a tank, and a skirt to make the Protank look good when attached to a standard ego battery system.