Hi Micha,
many thanks for the additional photos. I´m undecided about the red one in the middle...
Is there any difference in the quality of the copper collar? Does it perhaps have a seam line
at the back?
A characteristic of the Driburg copper parts is that they are slightly inward curved at the base.
They must have been pressed from a single piece - a technically highly skilled work.
Unfortunately nobody seems to know who made them and the rumour they tend to spread
in the museum about a certain german
Metal
Working
Factory won´t be
repeated here, because a friend of mine managed to disprove it...

Pictures tend to disappear from online storages after a certain time... Would it be ok for
you if I directly attached them to this thread, please?