I think I saw one of those before I knew what it was...
These days, of course, every serious tube enthusiast needs some sort of tester. I guess I'm out of touch but is there any reasonably priced modern tester? (My TV-7 is still going fine, but it won't last forever, and having tried to repair a Hickok tester in the past I can confidently say that I am out of my depth on that one...)