10 C. And 15 C. Merkur head, in each case as vertical pair with overprint in type I in the variety \"inverted overprint\", along with vertical pair 25 C. Merkur head with normal vertical overprint in type I, on properly franked letter from \"Rosendael 3-7 1940\" to Malo les Bains with arrival postmark on the back \"MALO LES BAINS 4-7 40\". Franking with insignificant perforation irregularity, otherwise very fine. Covers with this varieties are very rare, also the cancellation from Rosendael as well the arrival postmark Malo Les Bains come rare before! Photo expertize Gerhard Krischke