The Logitech TrackMan Marble gives you superior comfort – for either hand. Amofferextrous 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. Clean the button/key with compressed air.