The wheel provides easy scrolling and added convince of an extra button -Solid-state optical navigation technology provides superior precision and smooth navigation -Ergonomic design to support contour of palm for both right and left hand user -Advanced optical sensor for accurate positioning PRODUCT FEATURES : Accurate Optical Mouse, functional and comfortable The design of the mouse is comfortable for both right and left hand Fine optical system with a sensitivity of 800 dpi Plug and play USB interface Supports Win XP, Vista, 7 and 8