Blancpain’s Fifty Fathoms put together the features that define a diver’s watch, above all a rotating bezel that cannot be knocked out of place.

Historian’s noteThe 1953 date is Blancpain’s own. Its bezel patent was filed in 1954, while Rolex filed Submariner patents in early 1953. First to market is unresolved; first designed around timing a dive is Blancpain’s stronger claim.
SourcesBlancpain
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