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 USB Optical Scroll Mouse has no ball or moving parts, which improves its durability, makes it require less cleaning, and eliminates sticking. The mouse's comfortable, contoured shape fits either hand. Optical tracking is the latest advance in computer mouse technology. 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. There is no ball or roller to clog up so it works without cleaning.