Vision Spinner Variable Voltage Single Battery is perfect if you bought a starter kit that has a smaller battery, or one without Variable Voltage. The Vision Spinner 1100mAh battery has ample battery capacity to provide even the heaviest users with enough charge. The Variable Voltage can be increased or decreased in 0.1 increments by simply turning the spinner wheel at the bottom of the battery. The clearly etched numbers and arrow allow for precise control and setting visibility. Compatible with all eGo and 510 threaded clearomizers.