CRT Testers to look for.

[Olorin67]

Ive been wanting to get a CRT tester, any advice on which ones to look for? Mostly for B&W, but color capability would be nice also, since i have a late 60s Zenith 25" color set with a dim CRT, and was hoping it might respond to rejuvenation, or to test potential CRT donor sets before purchase.
Theres a guy in Kenosha with a basement full of test gear for sale, he had several, but I didnt know which ones were decent, or which to avoid.