The Aspire Vivi Nova BDC (bottom dual coil) has been revolutionized with a new heating element coil design. As bottom coil clearomizer types are becoming popular, the Vivi Nova BDC tank is reinforced with a plastic composite material and holds approximately 3.5ml of liquid capacity. The tank can be disassembled into five total parts for easy cleaning and maintenance. Coil heads can be easily replaced by unscrewing the bottom end cap. The plastic drip tip, that is included can be interchangeable with your favorite tip design and each unit includes one coil head (1.8ohm rating).