Newbie here, what's the meaning of oyster perpetual?

[Gazar]

As per title

[MsLucifer]

From my best friend, Google:

If one single innovation in the long history of Rolex—and there have been many of those over the last hundred years—can be said to have really put Rolex on the map, it was the Oyster. But what is the Oyster? The Oyster was the first successful waterproof case for a wristwatch, patented by Rolex in 1926. In those days, a waterproof and dustproof watch was a minor miracle. It was a technical challenge that had defied watchmakers for centuries, but the wily and imaginative founder of Rolex, Hans Wilsdorf, cracked the code and in the process set his company on the path to greatness and marketplace dominance.

Of course Wilsdorf was not an engineer, or even a watchmaker. Rather, he was a shrewd judge of the marketplace and an assiduous student of the watch technology of the time. Wilsdorf knew that if Rolex could be the first to make a waterproof watch a reality, they would have a unique product that future success could be built upon.

In their fascinating history of the company, The Best of Time: Rolex Wristwatches, authors Dowling and Hess catalog the long road that led to the successful Oyster. It was a tortuous process of design, more design, and then back to the drawing board. The final innovation that made the Oyster case a reality was when two Swiss inventors named Perregaux and Perret patented a screw down, moisture-proof winding crown for watches in 1925. Wilsdorf knew immediately that this feature, combined with the case that Rolex had already been working on that featured a two-piece, screwed-together design with a rubber gasket, was the ultimate answer to the riddle of how to make a truly waterproof watch. The winding crown poking through the case had always been a weak point in the earlier designs, allowing moisture and dust to enter. The screw down crown would fix that. Wilsdorf bought the Perregaux and Perret patent for Rolex and never looked back.

Wilsdorf, ever the relentless marketing genius, knew the groundbreaking watch needed a short, catchy, memorable name. (In fact, he is said to have picked the name Rolex for his company because it was easy to pronounce in virtually all languages.) Recalling the difficulty he had opening oysters for a dinner party, he was inspired to call the new watch with the tough, impermeable case the Oyster, and the rest as they say, is history. Rolex finally had something no other watch company did: a waterproof wristwatch. The modern watch was born.

In the 1920s when it was patented it was the ONLY waterproof wristwatch in the world, and could truly be called the first modern watch.

Rolex and its founder Hans Wilsdorf knew they had a world-beating watch in the new Oyster. They used their unique advantage for all it was worth. In one of the first marketing coups to come from it, Rolex asked Mercedes Gleitze—first woman to swim the English Channel—to wear an Oyster on a Channel swim. She did and Rolex followed up with a first page advertisement featuring a photo of Ms. Gleitze in the London Daily Mail, trumpeting its achievement:

“Rolex introduces for the first time the greatest triumph in Watch-making – ROLEX ‘OYSTER’ – The Wonder Watch That Defies The Elements. MOISTURE PROOF WATER PROOF HEAT PROOF VIBRATION PROOF COLD PROOF DUST PROOF--Miss Mercedes Gleitze carried an “Oyster” throughout her recent Channel Swim. More than ten hours of submersion under the most trying conditions failed to harm its perfect timekeeping. No moisture had penetrated and not the slightest corrosion or condensation was revealed in the subsequent examination of the Watch.” With this ad, Rolex pioneered the modern concept of sports celebrity marketing.

It was the Rolex Oyster and later Rolex Oyster Perpetual models that made the Rolex reputation for excellence. The Perpetual was the Oyster combined with an automatic winding mechanism that was wound by the wrist motion of the wearer. It was so famous that by the late 1940s Ernest Hemingway would immortalize it in his book, Across the River and Into the Trees when comparing the watch to the human heart: “It's just a muscle. Only it is the main muscle. It works as perfectly as a Rolex Oyster Perpetual. The trouble is you cannot send it to the Rolex representative when it goes wrong..."

The Oyster waterproof case was the basis for all of the subsequently successful models: The Datejust, the Explorer, the Submariner, GMT, Day-Date, etc. Today it lives on in the markings of the dials that read “Rolex Oyster Perpetual” followed by the model name. The modern Rolex Cellini dress watches are not Oysters, but the rest of the line is. This includes the overwhelming majority of watches sold by Rolex. Today’s standard Oyster model Rolex is guaranteed to be water resistant to 100 meters, a depth unimaginable in the 1920s. Diving model Oysters go even deeper. The standard Submariner is guaranteed to 300 meters, and the new Deepsea to a staggering 3900 meters.

A lot of other watch companies make pretty luxury watches, but nobody makes tough-as-nails mechanical watches that endure punishment and laugh at the elements like Rolex. That distinction is crucial, and Rolex owes much of its success to that unique market niche that the Oyster case helped define.

*article from Time & Gems.com