Double used letter of the bowery Sunga to Amani with arrival postmark, franked with horizontal strip of three 2 1 / 2 Heller \"imperial yacht\" and three cancellations the \"USAMBARA railway mail ZUG 6 a 1.5.15\" and repeated on the back use as pre-payment of postage in cash Tabora with three circle cancel \"Fr. According to Einn. Proof in Tabora\" and handwritten \"15 H\", cancellation \"TABORA\" to Amani, good legitimate condition, very rare, photo expertize Jaeschke L. BPP