This innovative commemorative postage stamp, Edifil No. 5250, was issued by Correos Spain in 2018 to mark the 200th anniversary of the birth of Cosme García Sáez, a pioneering Spanish inventor and submarine designer. Unusually printed on rubber rather than traditional paper, the embossed stamp features a portrait of García Sáez alongside an illustration of his pioneering submarine invention and a Logroño postmark. Its unconventional material and engineering-themed design make it a distinctive example of experimental philately, linking Spain’s postal heritage with the inventive legacy of one of its notable engineers.