So while my trackball at home is a discontinued Microsoft Trackball Explorer (actually have 2 in case one breaks, but both are pretty used), I carry a Kensington Expert Mouse trackball with me from job to job.
My discontinued Microsoft Trackball.
The Excellent Kensington Expert Mouse.
In fact before the Microsoft Mouse I always had a Kensington similar to this, even back to my Mac Classic I had an ADB model. The current model is a powerhouse with 4 buttons and an excellent scroll wheel.
Well under the ball, there are 3 little red plastic balls that the ball sits on, and one of mine came out when I was trying to clean it, and I lost it. And the ball just doesn’t track right, so I contact Kensington, and they don’t have the part, but are sending me a new trackball. And I just need to dispose of my old one! How awesome is that? THANK YOU KENSINGTON! YOU GUYS TOTALLY ROCK!
And I do love your trackball!