The Aspire K series refers to the e-cigarette models K1, K2, K3 and K4. These models are starter sets. These are due to the simplified operation especially for steam entrants who were previously smoker of tobacco cigarettes and now plan to switch to the electric cigarette. For example, the K2 set comes with the K2 Clearomizer, a pre-installed BVC head, and a separate spare head with a resistance of 1.6 ohms. Of course, a micro USB charging cable is also included with the e-cigarette with a battery capacity of 800 mAh. The successor K2 offers a higher battery performance (1200 mAh) and the K3 Clearomizer with a larger liquid tank of 2 ml.