Oyster: Here is the name that Rolex’s founder, Hans Wilsdorf, gave for the earliest water-proof watches from the twenties. “Oyster” remains the necessary metaphor for Rolex, and it reveals up in quite a few phrases, model names, and neologisms.Helium Escape Valve (HEV): Originally co-developed by Rolex and Doxa, that is a modest, spring-loade