RYBNIK 21.3.1921 ZKr (OS handbook number 293.1) on registered letter with 5 Pfg green, 10 Pfg orange red, 20 Pfg blue horizontal pair, 25 Pfg dark brown, 50 Pfg dark gray (at back) ironworks and dove to Munich, arrival postmark (23-3.1921) at back, rare cancel, time typical traces of age and usage