#294a, 1c Pan-American, Center Inverted, used, with light circular postmark, bright color and detailed impression, centered to the bottom, faults have been skillfully repaired, thus an affordable and visually-appealing example of this popular error and desirable rarity, particularly scarce used, fine appearance, with 1981 P.F. certificate. 300 stamps were printed with the center inverted, with the vast majority of those remaining in mint condition. Used examples, such as the stamp offered here, are accordingly rare.(Image)