PROSKAU 10.2.1921 ZKr (OS handbook number 266.1) on registered letter with 3 Pfg red-brown, 5 Pfg green two single stamps, 10 Pfg dark red orange block of four, 15 Pfg dark violet, 20 Pfg blue numeral of value 1920, 2 1 (2 Pfg grey vertical strip of three, 3 Pfg reddish brown vertical pair, 25 Pfg dark brown vertical pair ironworks and dove to Berlin Schoeneberg, arrival postmark (11.2.1921) at back, time typical traces of age and usage