TRACKBALL COMFORT Sculpted shape supports your hand and stays in one place—move 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.Wireless operating distance: Approx 10m