This mic appears to have been produced in the 1940’s era, possibly earlier bearing resemblance to the 737 series, but it also resembles a model 51 dynamic. The case is in excellent shape and it sports the original cloth braided cable. The bottom is threaded for a standard desktop stand. Indications are that this mic was intended for two-way radio.
There’s not a lot to a crystal mic which the layman can deal with and either the connections are good and it works, or not. That’s the easy part.
Time and humidity have certainly taken a toll on this rare antique. The steel back-plate almost looks like it’s galvanized.
I’ll keep you guys updated as the project goes along. If you know anything about these guys, drop me a comment, or follow along on the TSU posts and see what we come up with!