It is a sign on which the various NSDAP organizations could write their meeting times. Kind of a public bulletin board for organizational meetings. They are depicted in the Organisationsbuch der NSDAP. Some are RZM marked. Those that don't appear to be may have just rusted enough on the reverse to make the mark hard to see.
Richard V
I think that Bill Shea has one for sale on his website but it has been cut down. After the war a lot of these signs were used by people anyplace that a large metal panel could be used. If it was used in a place where the eagle side might be visible, the sign usually suffered lots of damage to disguise what it once was. I bought 2 that had been used to cover up some holes in a shed. One was in decent condition the other in very good condition. It was a pain in the *ss getting them over here to the States though.
Richard V
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