Ergonomic design:This mouse is design for users to reduces muscle strain and can even undo the damage that years of using a traditional computer mouse causes. Wrist pain, shoulder fatigue, Carpal Tunnel Syndrome and tendonitis can all be alleviated or, in many cases, eliminated with regular use.Adjustable DPI: The adjustable DPI settings allow you to change the sensitivity of the mouses pointer speed (800 / 1200 / 1600 / 2400), allowing you to decrease speed for tasks that require guaranteed precision or increase the speed faster for browsing.Rechargeable: This mouse doesnt need to use AA battery now .it have battery inside the mouse you just used USB cable chargingDid not need to worried to buy batteries again againWide Compatibility:IBM or compatible computer. Windows2000/ME/XPx64/Vista/7/8, Mac OS Xover V10.4An available USB portCustomer Satisfaction: 30-day Free Return and Refund,12-month warranty for vertical wireless mouse,24-hour Response Time for Customer Issues