DESC: Logitech Trackman Marble Mouse - Trackball - optical - 2 button(s) - wired - USB TRACKMAN MARBLE MSE USB PS/2The Logitech Trackman Marble gives you superior comfort - for either hand. Ambidextrous design provides long-lasting comfort for right- and left-handed people. Convenient button controls let you easily move forward and backward when you're surfing the web. Click the large buttons together and use the ball for auto-scrolling. Fingertip-based control enables fast, accurate cursor movements. Patented Marble optical technology ensures smooth tracking.