The Pen is a battery-free stylus that adopts the most advanced passive technology, with no battery and no charging required. This environment-friendly pen allows the constant uninterrupted drawing and playing, avoiding the low power interrupting your operation. And comes with 2 programmable express keys, one-click toggle allows you to switch the function between brush and eraser constantly. (8 Pen Nibs)– Extra 8 nibs are included for replacement. It will provide you precise control and accuracy at your fingertips, to bring more natural lines and enhance creative performance. (EXPRESS KEYS)– 4 customizable express keys could be set to more functions as you like. Using them while working will largely improve your workflow.