Overview: The USB Optical Scroll Mouse is a two-button mouse with scroll wheel that provides the speed and accuracy of optical tracking in a simple elegant design. It records motion precisely on a variety of surfaces using the latest optical sensing technology. The mouse's comfortable contoured shape fits either hand. Optical mice have a tracking system that works through light which means that there are less moving parts for greater durability than ball-based mice. The optical sensor within the USB Optical Scroll Mouse employs a scan rate of 800dpi. This optical system guarantees crisp motion tracking on many types of surfaces without a mouse pad.