25 C. Postal stamp \"Merkur head\" with overprint in type I, horizontal strip of four - left pair without overprint, right pair with overprint, properly franked more franking on letter from \"Ghyvelde 2.08.1940\" to Dunkerque with reverse arrival postmark from \"3.08.1940\", faultless condition - few perf tips tiniest gum spots (insignificant), expertise Lothar Herbst VP (2018) : \"the other condition is perfect. The stamps are only in very small number of pieces known, therefore are they rare. In this variety \"pair with overprint\" and \"pair without overprint\" is the franking very rare. \", Michel 1.000.-