TrackMan Marble Wheel combines an easy-to-use scroll wheel with the smooth motion and superior performance of Logitech's optical Marble technology. This gently curved three-button design features a trackball positioned for thumb control, and provides fast, precise cursor movement. ??Logitech's innovative wheel button is a true wheel that saves you time scrolling through documents in Windows or MacOS. With the scrolling wheel, you can scroll from wherever your cursor rests without having to move over to the scroll bars. Just turn the wheel. It's also this simple to zoom in Microsoft Office; you never have to touch your keyboard or take your eyes off your work. Clicking the scroll wheel gives you the ability to AutoScroll, allowing you to scroll diagonally or in any other direction by rotating the trackball. Scroll freely through documents, such as spreadsheets, which are larger than the screen and control the speed with the trackball.