USB with Battery Multipurpose Black & Silver with Charger
- 1. Button pen: Press the button to turn on/off, preheat and voltage settings. 2. Switch: Press the button 5 times to turn on/off. 3. Variable tension: Press the button 3 times to adjust the voltage: 2.6V green, 3.3V blue, 4.0V red. 4. Preheat function: Press the button twice to preheat. Press the button once to stop preheating..