Description: Mi.No. 41/42 SPECIMEN. After being accepted to UPU Independent State of Croatia was due to furnish UPU with 300 copies of their issue for the distribution to other UPU participants. Purpose for this was, for them to be recognized on incoming mail and thus the avoidance of postage due charges arising from the unfamiliaritiy with new issues. This SPECIMEN originetes from archives of Mauritania, a French colony that at that time was under administrative control of Vichy France, and stamps were probably forwarded to Mauritania from French postal authorities in Vichy. This is the first until now known SPECIMEN of NDH, even if quality is not the best in this case it is not the problem, because it is unique. Detail description can be find in Acta Philatelica 2018.