The Expert Mouse Wired Trackball is the ultimate productivity enhancer that makes working at the desk quicker, more accurate and extremely comfortable for your hand and wrist. Featuring DiamondEye technology, the trackball uses optical tracking to precisely follow small flecks embedded in the large 55mm ball to provide smooth, accurate cursor control. The four buttons are customisable using our highly intuitive TrackballWorks software, while our award-winning Scroll Ring lets you quickly scan up and down web pages and large documents. Add it all up and you get exceptional comfort and ease-of-use that has set the industry standard for more than 20 years. PC and Mac compatible. Movement detection technology provides smooth, precise cursor control so you can get where you want on the screen quickly with less hand movement, improving productivity and efficiency. Spin the dial to move up and down web pages or documents with complete ease while the grey ball has been specially designed with an absolute spherical, hard surface for precise tracking and control. Works equally well for both right-handed and left-handed users to get the most out of their trackball. Soft cushioning cradles the hand and wrist in ergonomic comfort for pain-free productivity during extended periods of activity on the computer. Free downloadable software provides an even more personalised experience, giving you the ability to assign a wide variety of program functions to each of the 4 buttons, as well as controlling the pointer speed and scrolling speed.