Battery Capacity : 2400mAh, biult-in 3x 800mAh lithium battery Charging time : 2-3 hours Operation time :Under normal 8V voltage, the voltage stable state can last for more than 10 hours,long time working the voltage is stable. Output fixed current ：1A Working voltage : 3.7V Output Voltage : 5V-12V LED display content : output voltage range + battery usage + working time Instructions for use: - Power ON/OFF: Long press "O" key for 3 seconds - Output pause / resume: Short press "O" key to pause the output, and short press it again to resume the output(the resume voltage is the working voltage before the pause). - Adjust output voltage: Press the "+" or"-" key to adjust output voltage. The voltage can be adjusted through button (+) and (-) respectively with the voltage of 0.1V on each press. - Working time: The working time can be accurate to minutes. When the power is turned off, the time will be cleared. When the output is paused, it will also stop counting. Power: The LED display will show the remaining power, and the full power will display 4 divisions. Fast charging through the matching fast-charging USB data cable can usually be fully charged in 1.5-2 hours. Please pay attention to the change of power at any time to prevent sudden power loss from affecting your tattooing work.