Technical Specifications of CLK!1280:Variable Voltage: The rotational wheel adjusts voltage in the following increments: 3.5, 3.8, 4.0, 4.3, 4.5, 4.8, 5.0 Standby current: 50uA maxMaximum output current: 3.5AMaximum output wattage: 15WClearomizer Resistance: 1.2 ohm (minimum), recommendation 2.5OhmBattery: Built-in 1280 mAh polymer Li-Ion rechargeable battery.Charging: Micro USB DC5V/500mAShort Circuit Protection: 0.6 +/-0.2 ohm Notice:The red LED will blink six times and turn off if the rotational wheel is not in place.To set your desired voltage turn the rotational wheel to the left or right until you hear an audible click.When adjusting the voltage with the rotational wheel always check to ensure the wheel is set to your desired voltage.