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 customizable 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.N/AN/ATrackballWorks lets you customize all 4 buttons set cursor speedN/AMac running OS X or later with an available USB Port.** Internet connections or CD ROM drives to install the software.** Compatible with Windows7 Windows XP Windows ViN/AKensington worked directly with Microsoft to provide professional-level solutions that look as good as they function so you can work like a pro.N/ADiamondEye optical tracking technology for premium cursor control and accuracyN/AAward-winning Scroll Ring lets you scan up and down pages with easeN/ALarge 55mm ball is designed as a perfect sphere to provide exceptional precisionN/ADetachable wrist rest supports hand and wrist for ergonomic comfortN/AReliable wired USB connectionN/AWired 180cm USB cable provides reliability and avoids need for batteriesN/ADetachable wrist rest cradles hand in comfortN/APC and Mac compatible