All the cool amp folks definitely hang out here...School me on this new found object. I was walking through a hoarder’s garage. His family was cleaning up the place. I saw some old tube-era test equipment. I lit up! I saw “Sprague” which we generally associate as higher quality e-caps. I took a closer look. A Sprague TO-4 capacitor tester. About 1952 era. I paid $15. Surely I took it home! Tell me what this brings to vintage tube amp nut. So far I think I can actually test for leaking DC coupling caps. Also prove if 50 year old e-caps are really leaky. Not that I really care. My belief is all old e-caps get swapped out. I also think I can re-form old caps? Or slowly warm up old caps in barn find amps? Is that right? What else? Cool tool? Or??? I’ve yet to try it. I found a manual and downloaded it. Tips and opinions appreciated.