German offical postal service Ostland, stamps from Ostland 4 and 50 pfennigs permanent issue Adolf Hitler with overprint Ostland, Michel number 3 and Michel number 16 in mixed franking, on correct franked registered official letter, cancelled by cancel "PCKOB * K * 18 6 43" and on the back arrival postmark from Prague, very fine, photo expertize Robert Brunel VP (2025)