The Oyster case constitutes an important milestone in the history of contemporary watchmaking. Invented by Rolex in 1926, it was the world's first waterproof case for a wristwatch thanks to its patented system of screwing down the bezel, case back and winding crown against the middle case. A symbol of robustness and waterproofness, this perfectly proportioned and elegant watch case is a superb blend of form and function, whether crafted in Oystersteel, 18 kt gold or 950 platinum.

  • The Strength
    of a concept

    Oyster Case

  • Today, thanks to the hermetic construction of their case, all Oyster watches are guaranteed waterproof to a depth of at least 100 metres (330 feet), and up to 3,900 metres (12,800 feet) for the Rolex Deepsea extreme divers' watch.

    The Oyster’s middle case (the central section of the case) is stamped and machined out of a solid block of Oystersteel, 18 kt gold or platinum. It is extremely robust and forms the backbone to which all the other parts of the case are securely fitted. Certain Professional models feature a crown guard on the side – these shoulders are stamped as an integral part of the middle case.

    The back of the Oyster case is hermetically screwed down against the middle case. The characteristic fluting on Oyster case backs, a legacy from the Oyster of 1926, fits into a special tool exclusive to authorized Rolex watchmakers, so only they can access the movement.

Crowned with success


A little masterpiece of technical prowess, the winding crown of Rolex watches is made up of about 10 parts, and is screwed hermetically onto  the watch case. This is how Rolex, for the first time in the history of watchmaking, crafted a waterproof winding crown — a secure interface between the protected, sealed world inside the watch and the harmful elements of the outside world.

Rolex Twinlock and Triplock winding crowns use two or three sealed zones to ensure watertight security akin to a submarine’s hatch.

Watchmaking oyster-case winding crown

The Oyster case constitutes an important milestone in the history of contemporary watchmaking.

Cyclops lens

A magnifying lens patented by Rolex in 1953 to enlarge the emblematic date of the Datejust. Named after the one-eyed giant of Greek mythology. A signature feature of Rolex watches, easily recognisable from a distance. Made of the same scratchproof sapphire as the crystal to which it is affixed. Featuring a double anti-reflective coating to ensure extra-clear legibility of the date.

Watchmaking oyster-case cyclops lens
  • The Bezel

    Form and function

  • At Rolex, form and function are often closely intertwined. This is particularly true of the bezel, an essential component in the  strong visual identity of Oyster watches. Bezels in a wide variety of forms, fixed or rotatable, have been introduced over the years, offering new functions according to the watch type: diving time, second time-zone, 24-hour display, tachymeter scale, etc.

    Originally, the fluting of the Oyster bezel  had a functional purpose: it served to screw the bezel onto the case helping to ensure the waterproofness of the watch. It was therefore identical to the fluting on the caseback, which was also screwed onto the case for waterproofness, using specific Rolex tools. 

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