Toshiba PA3571U-1ETA 3-Button USB Optical Tilt-Wheel Scroll Mouse Mice It sets a standard for comfort and dependabilityand is great for both home and business users. The optical engines 800 dpi resolution offers dependable accuracy with smooth cursor on most surfaces. Work comfortably all day with the balanced and weighted design. Its 4 way scrolling provides you anexceptional navigation experience and the abilityto scroll applications vertically. You can also push the wheel to scroll pages horizontally including web pages, Word documents and Excel spreadsheets.