Operating Voltage: 4.5-12 V Battery capacity: 1950 mAh Battery working time: 6-8 hours Charging time: About 2 hours Battery interface: type-C Recommended line working voltage：8-9v Recommended shader working voltage：6-8v Power-pack key features: Display in which you can view voltage, Remaining battery reminder. Adjust output voltage: Press the "+" or"-" key to adjust output voltage. The voltage can be adjusted through button (+) and (-) respectively with the voltage of 0.5V on each press. The motor of this cordless tattoo gun has excellent performance for color packing, which can improve your work efficiency, at the same time, this customized motor will cause less damage to your customer's skin than other machines, which will make you win a good reputation. When you need to change the stroke, it is easy to control and very convenient.