German offical postal service Ostland, 12 pfennigs postal stamp with overprint Ostland in mixed franking with stamps of the German Reich, Michel number 512, 513 and 519, on correct franked registered cover to Stuttgart, registration label with single line cancel "Pleskau" and official seal of the post office Pleskau, cancelled "PCKOB * K * 21 5 42, photo expertize Robert Brunel VP (2025) "the condition is perfect