SteelSeries World of Warcraft Wireless Mouse includes lithium battery - The SteelSeries World of Warcraft Wireless MMO Gaming Mouse is a finely crafted tool, freeing the citizens of Azeroth from wires while still delivering the perfect weapon for your battles and adventures across all your MMO worlds. Featuring proprietary 2.4 GHz wireless technology and outstanding battery life, it can also charge while you play in wired mode. Brilliant illumination on both the mouse and the charging pedestal functions with 4 levels of intensity and pulsation. 11 programmable buttons feature the ability to be customized via the SteelSeries Engine and work with all MMOs.