It's an EMR pen, so doesn't need batteries - as long as you check that it's compatible with your device, then it works perfectly. I'm using with a Lenovo Yogabook on the halo keyboard. Doesn't have the ink capabilities that the original Lenovo pen has, but it's a fraction of the price and works perfectly in Whiteboard, Paint, or other apps that allow free-form input.
does not work. nowhere to insert batteries, no buttons to connect with computer and computer doesnt even recognise stylus without it being connected. do not buy