Soft rubber coating, offers excellent hand feel. Scroll wheel made of silica gel, is precise and feels comfortable. Its ergonomic shape eliminates forearm twisting and offers better relaxation of fingers. High definition optical mouse. Laser technology provides more precise, responsive and smoother tracking delivery. Work on any surface. Plug-and-play USB connection. Adjustable Tracking Resolution: 400 / 800 / 1600 / 3200 DPI. System requirements: Windows® 98, 2000, 2003, Me, XP, Vista, Linux, Mac OSX 10.2 or above. 4¾ x 2¾ x 2¾ in.