ELECOM M-XT3DRBK Wireless Trackball Mouse, 6-Button with Smooth Tracking Function, Video Gaming Sensor, Black Advanced Responsiveness  An innovative wireless mouse with precision optical sensor, the thumb trackball offers superior movement and pin-point accuracy Comfortable, Ergonomic Design  Keep your hand and wrist more stable with our streamlined design that improves natural comfort, feel, and movement 6-Button Key Binding  Each trackball mouse boasts 6 unique thumb and finger buttons for binding keys for web surfing, playing MMOs, or fast-twitch shooting Adjustable Resolution  Get the blazing responsiveness or steady pathing you need by switching between 750/1500 resolution; perfect for home or office use Robust Wireless Connectivity  Enjoy the same flawless response you get from a wired mouse with our design thanks to the premium 2.4 GHz connection