J5, J11, J16 (D8, D17, D23) 1931 Postage Dues cover with 75¢ black on orange left sheet-margin example, 25¢ black on rose (Setting B) horizontal pair, and 15¢ black on orange horizontal pair, each stamp tied by "Zanzibar" cds to small philatelic cover addressed to "The Post Master", the 75¢ is an astronomically rare and vastly undercatalogued used stamp!
