I am trying to find info on or from collectors of old detectors. I have a M-Scope from the 50's and would like to know more about it than I got from Fisher's website. Anybody got a 'History of Metal Detectors' type book? This model has a blue case made of wood by Fisher himself and the headset is bakelite and I think with new batteries it may still work. I was told that the year of manufacture is in the serial number but of that I am not sure. It takes some C cells and a 67&1/2 volt battery.