United States. (Prisoner of War Mail). 1919. Envelope headed 'American Y.M.C.A./ Paris Branch' addressed to 'Comite International de la Croix Rouge, Agence Internationale des Prisonniers de Guerre, Geneve' bearing United States SG 436, 5c Prussian blue (not tied) with boxed 'Passed By Base Censor/ A.E.F.' in carmine with 'Examined by Base Censor' label, circular '171' and 'Controle Postal/ Militaire' label tied by oval 'Ouvert/ Par l' Autorite Militaire/ 126' in violet on face and reverse. Very attractive item.