I've been trying to place a date on this piece and have been unable to do so. As near as I can tell, it looks to be from '47-48, but it's really hard to say. I've checked the registry and have tried several advanced searches, but can't seem to find much on this particular 20 ohm version.
Just curious if any members have a bookmark to share or can recall anything from the past on this subject?
Here are some photos to show what I'm talking about...