MODERN RARITY 18ct Flag #6 tied on small cover, early use, ONLY 21 KNOWN covers

Description

Outstanding cover with the 18ct Flag #6 tied on a #6 size cover by 10/8/81 Hillsboro, WI cancel. This is the only known cover usage of this plate number from Wisconsin. Cancel does NOT touch the plate number. Stamp is at least VF and good perfs all around. Cover is clean and undamaged. There are only 21 known covers of this plate number, and only 6 on #6 size cover. NONE have been found in the past decade. Considering the small cover, the quality of the stamp and the cover, and the early usage during the short 18ct first class rate, this one is one of the best covers of this pnc in existence. A modern postal history classic and a real bargain at 50..