8 (72) 1929 Sept 5 domestic cover to a Military unit, franked by block of eight 1¢ black K George V overprinted "G.E.A." (SG Type 3), tied by "Exhibition P.O. Tanganyika" cds with "Camp Post Office, Dar-es-salaam Sep 6, 1929" receiver on back and an Antwerp 1930 International Exhibition multicolored Commemorative sealing the flap, interesting and scarce.