Microsoft Natural Ergonomic Keyboard 4000 – As Is

After recently buying this online, and being told that it worked, I found that some keys malfunction. Perfect physical condition otherwise. Comes in original box with Installation CD included for Window 2000 and XP; Mac OS X V 10.1.5 – 1.3. Angled keyboard with reverse slope attachment and cushioned palm rest. Many hot keys, forward and back buttons and a zoom slider. USB connector. This is the wired version. "Breakthrough ergonomic keyboard design with improved design promotes a more natural hand, wrist, and forearm position for greater comfort. Perform common tasks, like opening documents and replying to e-mail, with the touch of a button." Pictures are of the actual box.