Adjust the voltage between 3.0V and 3.8V with 3 clicks of the button. The battery has a built-in capacity of 320mAh and the cart can hold either 0.5ML or 1.0ML. The pen measures 115mm x 20mm x 20mm and charges with Type-C (cord not included). It has an auto-draw function and a pre-heat feature activated with 2 clicks of the button. The packaging, which measures 128mm x 30mm, has a strong magnetic closure and can be turned on or off with 5 clicks of the button.