1942 letter sent Prague pneumatic-tube post, franked by stmp A. Hitler and Linden Leaves in/at general value 6 Koruna, CDS PRAGUE 7/ 9.IX.42-15, on reverse arrival postmark PRAGUE 31/ 9.IX.42-16, mounted rose label Pneumatic tube post and express; oblong envelope with vertical fold - conforms way transport, rare usage!