The Aspire Nautilus Clearomizer has a revolutionary new design that consists of features based from vape enthusiasts who have provided feedback of what an ideal tank should be. Utilizing this information, the engineers have created a new tank that provides optimal performance and superior vaping functionality. This tank is really a work of art and holds about 5ml of eliquid (twice the amount of what protank holds) Updated bottom dual coil and don't forget the most important part which is the air flow control.