These are the new CE8 Rebuildable eGo tank clearomizers. They allow you to see how much liquid is in the cartomizer, while not compromising any performance, or worrying about filling in the cartomizer to wear out.  The eGo clearomizer holds approximately 1.6ml.

They come standard with 1.8ohms Resistance but with the rebuildable feature you can choose to purchase 1.8, 2.4 or 2.8 ohms resistances. Mouthpiece screws down, onto another o-ring providing an outstanding seal to prevent leakage. The oversized coil is designed for a high level of durability, coupled with the new center feed system provides outstanding results. The feed system to the coil on these clearomizers produces a very clean, and plentiful vapor. Unlike some other transparent plastic cartomizers these are designed to carry friendly without worrying about them breaking.