n the late 1930s, Panerai made a number of Radiomir watches with a special 12-sided bezel, engraved with the words “OFFICINE PANERAI – BREVETTATO”. This inscription referred to the patented luminous substance Radiomir used on the dial, and it suggests that the watches were used not for military operations but for presenting to the authorities of the Royal Italian Navy, which was evaluating new instruments for underwater missions.