Rechargeable Battery- Built-in rechargeable battery. You no longer need to buy batteries, very convenient!! EASY TO USE - One USB receiver at the bottom of the mouse, Just Plug and Play! Ergonomic Design-Scientific ergonomic design encourages healthy neutral "handshake" wrist and arm positions for smoother movement and less overall strain. More Adjustment-800 / 1200 / 2000 / 3200 DPI Resolution Optical Tracking Technology provides more sensitivity than standard optical mice for smooth and precise tracking on a wide range of surfaces. Useful Page Buttons-Added next/previous buttons provide convenience when webpage browsing; the superior choice for internet surfers, gamers and people who work at length at the computer. Wide compatibility-Compatible with Windows 7/8/10 / Vista / XP / 2000, Mac OS, Linux (NOTE: the forward and backward buttons are not recognized on Mac). Plug and play.