Material : aluminium alloy and high quality insulating plastic.Connector :RCA/DC/AudioBattery : 3x 600mAh lithium batteryCharging time : 1.5-2 hoursOperation time : Under normal 8V voltage, the voltage stable state can last for more than 5 hours,long time working the voltage is stable.Output fixed current：2AWorking voltage : 3.7VCharging voltage : DC 5V±0.5V 1000mAhOutput voltage : 5-12VLED display content:output voltage range + battery usageInstructions for use:Power ON/OFF: Long press "O" key for 3 secondsOutput 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. LED display shows 1-8 gears, corresponds to 5-12V.Gear description: divided into 8 gears. Different output voltages will show the corresponding gear on the LED screen. The 1st gear indicates that the output voltage is 5V, the 2nd gear indicates that the output voltage is 6V, and so on, the 8th gear indicates that the output voltage is 12V.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.