This striking 160-centavos México Aéreo stamp was issued in 1976 to promote INTERPHIL ’76, the International Philatelic Exhibition held in Philadelphia. The design is famous for its printed perforation gauge, ranging from 11 to 14½, allowing collectors to measure perforations directly from the stamp itself. At right, bold red typography highlights the airmail denomination, paired with the exhibition’s modern emblem and bilingual inscriptions. A favorite among thematic collectors of philatelic exhibitions, metaphilately, and unusual design concepts.