DPI optical sensor provides smooth and precise optical tracking on a wide variety of surfaces. Ambidextrous design is equally comfortable for both left and right-handed users. Extended 125cm (4.1ft) cord length for versatility. Sure-grip textured scroll wheel for quick and efficient scrolling through web pages, documents, or long lists. One-step installation: simply connect to a free USB port on your computer and you're ready to start clicking! Easy-glide feet reduce friction and slide effortlessly across any surface.