The man's unit is handwritten on the card. I just can't read it because I would have to stand on my head, which is not recommended for those of my age. If you could turn the reverse side of the card upside-down, perhaps we could decipher it.
Well, all I can make out are the first and last, Abs. (Absender) and Königsberg. I'll show it to a couple of Germans, who know how to read Sutterlin. We'll see if they can add anything.
