Wireless trackball features a stable, sculpted trackball that supports your hand and lets you rest your arm to keep you working comfortably all day. Unifying receiver stays in your computer and lets you add compatible devices as you need them. Trackball delivers up to 18 months of use from a single AA battery. Wireless technology gives you the reliability of a cord with cordless convenience and freedom without any delays or dropouts. Programmable buttons allow you to customize your trackball's buttons to help you do what you want faster.