Microsoft Compact Optical Mouse 500 - White Microsoft Optical Technology: High performance Optical Technology - no mouse ball. 800 dpi optical sensor delivers greater accuracy and control. Scroll Wheel: Move through your documents quickly without having to click on the on-screen scroll bar. Comfort: Get a grip with a comfortable design created for either hand. Compact: Easy to carry along and use on small work spaces. Easy to Set Up and Use: No software to install, no feature setup required.