The Kensington Expert Mouse trackball features four buttons and a large trackball in a symmetrical, ergonomic design for right- or left-handed use. It also offers auto scroll and includes a set of predefined pop-up menus with shortcuts for Microsoft Word, Netscape Navigator, and other applications. In addition, the trackball comes with MouseWorks software for creating personalized shortcut menus of your own, as well as timesaving options such as adjusting cursor speed, changing double-click and drag protocols to single-click operations, and snapping the cursor to the default button of a dialog box. The large trackball lets you control the cursor with minimal hand and arm movement, and the four extra-large buttons include identifying outer ridges for use without looking. The Kensington Expert Mouse trackball comes with a five-year warranty and free technical support.