Constructed of high-grade Pyrex glass and stainless-steel finish the tank has a 5mL capacity, utilizes adjustable airflow control up to 4 positions from 0.9mm to 1.8mm air holes, incorporates Bottom Dual Coil technology and removable 510 tip. Its modern, elegant design makes for the perfect tank and its advancements allow for great wicking and no dry draws. With a simple twist on the lower ring, the user can select from four different options for a more precise session. Once you make your selection, a nice audible click will be heard, and the lower ring will lock into place. Enjoy pure, clean taste with the Nautilus Tank by Aspire. At a great price, get one today!