Microsoft IntelliMouse Optical is the solution. Microsoft have replaced the old-fashioned mouse ball with an IntelliEye optical sensor that tracks movement 1, 500 times per second - providing smooth and precise motion. No mouse ball means no moving parts to clean or wear down. And, the optical sensor is sealed in to keep out the dirt and lint that can cause a traditional mouse to skip or jam.

Ergonomic Design - Allows the user's hand to rest naturally on the mouse for maximum comfort. The shape of the Intellimouse Explorer supports the entire hand and fingers, while the slope helps keep the hand and forearm naturally aligned

Microsoft Optical Technology - Optical technology refers to the use of an optical sensor to track mouse movement, rather than the traditional use of mechanical parts. As a result, optical mouse products work on most surfaces and offer you better durabilit

Left- or Right-Handed - Work in comfort, whether you mouse with your left or right hand. Ambidextrous design makes it comfortable either way

USB Connectivity - Connects to a rectangular Universal Serial Bus (USB) port for plug-and-play convenience

Scroll Wheel - Navigate documents and Web pages effortlessly without using the on-screen scroll bar, saving time and effort

PS/2 or USB - Take advantage of total flexibility with two connection options. You can connect to either a round PS/2 port or a rectangular Universal Serial Bus (USB) port for plug-and-play convenience

Maintain and optimize applications

Internet Buttons - Buttons let you go Back and Forward on the Internet with a single touch

PC and Mac Compatible - The rectangular Universal Serial Bus (USB) plug connects to a Windows- or Macintosh-based computer. The included IntelliType Pro keyboard software comes in a Windows or Mac OS version (Mac OS 10.1 to 10.1.3)