45 C. Postage stamps issue "Merkur head" and 55 C. Charity issue "ambulance service monument" with hand stamp overprint in type I, correctly franked mixed franking on letter from "Dunkerque 21.07.40" to Ghyvelde with on the back arrival stamp from 22.07.1940, faultless condition, unsigned, expertise Lothar Herbst VP (2018) : "the condition is perfect. The stamps are only in very small number of pieces known, therefore are they very rare. ", Michel 1.100.-