HINDENBURG, 3 Mark dark violet vertical pair, Steelworks and Dove of Peace 1920 as multiple franking on registered letter to Basel / Switzerland, double-circle HINDENBURG 21 6 22 g (OBERSCHL) 1 (OS handbook No. 119.10), arrival (24.6.1922) on reverse, passed German currency control in Munich: two-line boxed R2 Freigegeben P. Ue. München (OS handbook No. VII B 2), age and use marks typical of period