HP Ultra Slim Mini 2.4G USB 2.0 Wireless Mouse -  Black with 3 buttons is powered by 2 AAA batteries (Not included) with ON/OFF switch. Flexible to Adjust optical sensor from 800 dpi to 1600 dpi and Great for Netbook User! No More large USB dongle sticking out on the side of your Notebook / Netbook.  It transmits for up to 7 meters operating distance‎‎.‎‎‎‎ No need for a special driver‎‎‎‎,‎‎ ‎‎just plug‎ and play‎‎‎‎.‎‎‎‎ It is Ergonomically designed‎‎‎‎,‎‎‎‎ and comfortable to use‎‎.‎‎