H&G DB1, 1939 2.25fr Red brown and blue, large-sized envelope prepared for UPU Congress members, postmarked Alger and addressed to "Madame James H. Knox, Delegation de Etats Unis d'Amerique, Buenos Aires", light toning and some edge wear, still fine and very rare, these envelopes were created to mail special presentation booklets which were prepared for each delegate of the UPU's 11th Congress, the only examples available to collectors are those obtained from the few delegates who disposed of them