Amazon.com has the Kensington Slimblade Trackball USB 2.0 for PC and Mac, K72327US for $101.97, 21% off + Free shipping. Features: Multi-function ball lets you easily navigate through your music, pictures and documents using media or document view mode. Gain fingertip access to image and media controls. ontrol cursor and scrolling; volume, play/pause, stop, and next; zoom in/out, and pan, all with the ball