The first TUDOR divers’ watch was presented in 1954. It bore the name TUDOR Oyster Prince Submariner, reference 7922. It was a self-winding watch unique in the brand’s collection. Its features corresponded to its function as a divers’ watch: a case with a screw-down back and a crown whose waterproofness was guaranteed to a depth of 100 metres, large hour markers and hands with luminous material for easy reading in deep water, as well as a bidirectional rotatable bezel graduated in 5-minute intervals to precisely measure dive time and allow for the adjustment of the decompression stages. Its black lacquered dial, subtly domed, was designed to optimise contrast with the indications it bears the gilt inscriptions OYSTER PRINCE at noon under the brand logo, and 100 m 330 ft, SUBMARINER, ROTOR, SELF-WINDING on four lines at 6 o’clock. There is also a reminder of its guaranteed waterproofness at 6 o’clock, in metres and in feet. Its Tropic-type Plexiglas crystal was dome-shaped for better wa ter pressure resistance. Its movement was the self-winding calibre 390, developed on a Fleurier movement-blank with a frequency of 18. 000 beats per hour.