IMO the king of the trackballs, Microsoft Trackball Explorer. I thought I had lost the ball but just found it - you can see the amount of use from how the paint
Microsoft Trackball Explorer 1.0 USB - Tested Works | eBay
Microsoft Trackball Explorer - Trackball Mouse Reviews
Microsoft Trackball Optical Mouse | eBay
Trackball Comparison: Wondering how Kensington Expert/Ploopy/Deft Pro/MS Trackball Explorer Stack Up? : r/Trackballs
Anyone know how to fix a trackball that feels like it's not smooth? I cleaned this Microsoft Trackball Optical mouse the first time and at first, it was smooth. And it's not
Microsoft Trackball Optical - Trackball Mouse Reviews
Microsoft Trackball Explorer 1.0 Mouse PS2/USB Compatible X05-87473 Tested Works | eBay
Microsoft Trackball Explorer 1.0 Mouse PS2/USB Compatible X05-87473 Tested Works | eBay
Microsoft TrackBall Optical
Microsoft Trackball Optical 1.0 PS2/USB Compatible Missing Trackball PARTS ONLY | eBay
Vintage Microsoft IntelliMouse TrackBall PS/2 - Huge Computer Mouse - Works 100% | eBay
Microsoft Trackball Optical 20 years after its release : r/Trackballs
Microsoft Trackball Explorer - Trackball Mouse Reviews
A New (To Me) Microsoft Trackball Explorer - deskthority
Microsoft Trackball Explorer 1.0 USB - Tested Works | eBay
Microsoft Trackball Explorer - Trackball Mouse Reviews
Microsoft TrackBall Optical | "Dude — your mouse is HUGE!" W… | Flickr
Microsoft IntelliMouse TrackBall - Higher Intellect Vintage Wiki