1. LED Display: Rotary tattoo pen machine has LED screen shows operating voltage and 0.5V voltage adjustments, and the adjustable voltage is 5‑12V. 2. Built in Battery: Wireless tattoo machine runs on 2000mAh lithium ion battery and can be operated continuously for a long time. 3. Timing Function: LED tattoo pen with timing function, convenient for tattoo artists to confirm the time of work, effectively improve efficiency, is the ideal choice for tattoo artists. 4. Cartridge Needle: The handle has a rolling ball design, you can better control the stroke length of the needle, and the tattoo pen is suitable for most of the cartridge needles on the market. 5. USB Rechargeable: Tattoo machine with USB C port, suitable for most chargers as well as mobile power, which is convenient for you to charge anywhere, anytime. Specification: Item Type: Wireless Tattoo Pen Material: Alloy Tattoo Pen Size: Approx. 15.7 x 3.2cm / 6.2 x 1.3in Function: Liner Shader Charging Interface: Type C Operating Voltage: 5-12V Battery Type: 2000mAh lithium ion battery (built in) Applicable Needle Type: Cartridge needle How to Use: 1. Install the cartridge needle, long press the power button to turn on the machine, short press the power button tattoo machine start, then start timing, press +‑ to adjust the voltage, each time 0.5V, adjustable voltage 5‑12V. 2. Short press the power button to pause, long press the power button to shut down. 3. If the first long press not on, it may be out of power, please charge first. Package List: 1 x Tattoo Pen 1 x Charging Cord 2 x Rubber Ring Note: There is an insulating piece between the upper power supply and the central color circle of the tattoo pen, rotate the tattoo pen to take out the insulating piece before the machine can be used normally.