To turn the device on/off, click the power button five times within 2 seconds. If a cartridge is attached, the digital display will show a countdown as the battery preheats. To change the voltage mode, double-click the power button. This will scroll through the three preset voltages shown as 1, 2, or 3 on the display. Mode 1, 3.2V Mode 2, 3.6V Mode 3, 4.0V. Press and hold the power button for up to 10 seconds to vape and inhale from the vape cartridge. The Lookah FIREBEE can be used with Lookah 510 thread vape cartridges and many 510 threaded prefilled and refillable cartridges