TrackMan Marble+ combines an easy-to-use scroll wheel with the smooth motion and superior performance of Logitech is patented, optical Marble technology. This gently curved three-button design features a trackball positioned for thumb control, and provides fast, precise cursor movement. Logitech is innovative wheel button is a true wheel that saves you time scrolling through documents in Windows 95 and Windows NT 4.0, and it is also a third, customizable mouse button for extra convenience.??With the scrolling wheel, you can scroll from wherever your cursor rests in any Windows 95, Windows NT 4.0, or Internet application without having to move over to the scroll bars. The advantage of optical Marble sensing technology Patented, optical Marble sensing technology eliminates the moving parts of mechanical trackballs. A laser-like beam illuminates dots printed on the ball, while an optical sensor tracks the motion. This gives you precision, reduces wear, and ensures smooth tracking, eve... Minimize