Marble® Mouse Get more comfort in an advanced trackball. Comfort Sleek shape: Delivers all-day comfort for either hand. Precision Optical Marble® technology: Tracks smoothly and precisely. Control Large trackball: Improves control while reducing hand and wrist motion. Multiple scrolling options: Use forward and back buttons, or auto-scroll with the ball. Customizable buttons: Personalize your controls for productivity (with included MouseWare software). System Requirements PC Windows® 95, Windows® 98, Windows NT®, Windows® 2000, Windows® Me, Windows® XP, Windows Vista™ USB or PS/2 port (Windows® 98 or later for USB) CD-ROM drive Mac Mac OS® 8.6 or later USB port CD-ROM drive Package Contents Logitech® Marble® Mouse MouseWare® Software User guide on CD-ROM USB to PS2 adapter 3-year warranty