This is a Prototype 10-12 Tube Tester that is calibrated and fully functional. I believe this was a predecessor tube tester to the 10-12 that was never produced. The rectifiers are solid state. There is a Gas switch that is not connected. I assume that it was planned to have a Gas test, but was not implemented.
It doesn’t have a roll chart, but you can use the settings from the 10-12 tube tester to test tubes. You can download the 10-12 tube tester Manual and Test Data here Tube Tester Manuals.
The Tube Tester is $250 plus shipping to the lower 48 states only because of the weight. Contact Me if you are interested.