PARA VOLT FOB METER, 1920's

Engineers pocket voltmeter. And the original box.
120 Volts Dc could have been the local mains voltage before 1930.

Your comments:

• These meters, of which I have quite a collection, were used to measure the plate (i.e. anode) voltage of thermionic valves and their grid voltages. Typically the plate voltage was about 90V DC, as were the batteries used in 1930's radio/wireless sets. The lower voltage range was used to measure the voltage of the battery supplying power to the heater of the valve.
  .......... Hans Walraven, Hoorn, Netherlands, 23rd of November 2010
  
  
• Still Have my grandfathers from the 1920;s and it still works
  .......... Ray Nock , West Brom UK, 21st of August 2010
  
  

A0301