My new 6 digit voltmeter.
Is there someone who knows more about is. It has not a moving coil meter ( i do not know the englisch term, it is sort of thermic, there ia a coil or resistancewire, I think this heats the circulair formed strip and the shaft is connected to the end of that iron strip, if the strip heats it expands and moves the shaft ( in Dutch weekijzeren kern meter or 1:1 translated weak-ironcore meter)
It draws about 300 mA at 6V.
I think they are used automotive to test batteries. I think it is from the 1920's. There is no brandname on it. The back opens if you push the top and the test wire is spooled on a reel in there to store it.
Resistance wire and test wire is cotton isolated, no rubber or so.