3 Kc. Airmail with overprint "Karlovy Vary 1. X. 1938 plus swastika", neat cancelled Karlovy Vary 1 4. X. 38 4 d on piece, issued only 25 examples - one of the large rarities the Sudeten territory philately, expertized as well photo expertize Max Mahr BPP and expertise Robert Brunel VP (2021) "the condition is perfect. Very rare", Michel 1.900.-