The comfort of a mouse -- the benefits of an optical trackball Control your cursor with a simple touch of the finger! The highly accurate Orbit® Optical is as easy to use as a regular mouse, but it stays in one place saving you valuable desk space. The precise optical tracking mechanism is also resistant to dust, reducing the need for regular trackball cleaning. Model number: 64327EU Features DiamondEye™ optical technology for precise tracking and cursor control The comfort of a mouse and the fingertip control of a trackball Uses less arm movement and desk space than a conventional mouse USB and PS/2 connectivity for greater compatibility Kensington's unmatched satisfaction guarantee - five-year warranty, toll-free technical support, and 90-day no-risk trial