Microsoft Trackball Optical. Borrowed one 20-years ago when I hurt my shoulder snowboarding. The person who loaned it to me then left the company and told me to

Microsoft Trackball Optical. Borrowed one 20-years ago when I hurt my shoulder snowboarding. The person who loaned it to me then left the company and told me to keep it. Still using it. Haven't had to use a mouse since. Never did like mice as used to find when overly focussed on something I'd end up half way across the desk without noticing.