Air mail envelope to New York; 1 July 1953. Red ‘1’ direction number. Franked with 100+150+150+30=430 groschen. 1 July was the first day of Kotal's period 10, in which the rates were 240 for an up-to-20 gram surface letter plus 150 air surcharge per 5 grams; so 390 for a 5 gram letter, 540 for a 10 gram letter. However the franking is correct for the previous day (!), Kotal period 9, at 240 surface plus 190-per-5 making 430.