10 C. \"Merkur head\" and 90 C. \"peace allegory\" with overprint in type I, properly franking on Brewed f from \"Dunkerque north 27.7.40\" to Ghyvelde with on the back arrival cancel from 28.07.1940, faultless condition, expertized Calves and expertise Lothar Herbst VP (2023) : \"the condition of the stamps is perfect. The letter became two-sided opened. The stamps are only in very small number of pieces known, therefore are they very rare. \", Michel 800.-