Logitech M570 Wireless Trackball Mouse &ndash; Ergonomic Design with Sculpted Right-hand Shape, Compatible with Apple Mac and Microsoft Windows Computers, USB Unifying Receiver, Dark Gray TRACKBALL COMFORT - Sculpted shape supports your hand and stays in one placemove the cursor without moving your arm CONVENIENT CONTROLS - Easy-to-reach Back/Forward buttons makes moving quickly between documents or browsing your favorite Web sites a breeze LONG BATTERY LIFE - With up to 18 months of use from a single AA battery, you might just forget your trackball uses batteries at all EASY TO CLEAN - Should you need to clean your trackball, removing the ball is a snap PLUG'N'PLAY CONNECTION - Nano-sized Logitech wireless unifying receiver stays in your computer plug it in, forget it, even add compatible wireless devices without multiple USB receivers