The Ultimate Trackball! The best trackball ever made has just gotten better. Designed for PCs and Mac's, the new Expert Mouse employs Kensington's Diamond Eye optical technology for smooth, precise cursor movement. Surrounding the ball, we have a brand new implementation of our award winning Scroll Ring that puts scrolling right at your fingertips. More comfortable than ever, the Expert Mouse even comes with a soft new wrist rest-right in the box! You get all of these great new features along with the same, large ball, exceptional control, and ease-of-use that has set the industry standard for more than 15 years.
I have used the original track ball made by Kensington years ago, and got my original experience from video games at the arcade. I've used them for CAD, and it is a lot more practical to have it on my desk in one place, and not have to fumble around with a "mouse". I have had two or three different track ball models over the years and they seemed to have changed the size of the "ball". The one I have now has a laser pickup, which I end up having to clean the dust out of every once in a while. The scroll wheel seems to stick some times and I haven't found a way to clean it yet, and the texture of the scroll wheel gets finger grime build up. I would like it if they had a "ball" eject feature so you can take the ball with you, as a security feature so other users can't use your workstation. I've tried to replace it with a billiard ball (I liked the weight) but the coating on the one I have is required for the laser to work.
What's great about it: It stays in one place on your desk.
What's not so great: Slightly prone to dust build up.