Kensington Turbo Mouse Pro USB Trackball with 6 Direct Web Buttons USB for Windows or Mac - 64214 Kensington Edge: This mouse trackball delivers when you have a need for speed through multiple turbo features. The heavy ball with progressive speed control is so good and so easy to use, you'll wonder why the mouse was ever invented. 10 buttons - 6 DirectLaunch buttons instantly take you to your favorite Web sites and 4 customizable mouse buttons streamline the tasks Large ball for precision pointing and easy control combine with steel bearings for smooth cursor movement and durability. Rubberized scroll wheel speeds through long documents and Web pages, Windows or Mac compatible