The Oyster case is one of the foundations of the reputation for excellence of Rolex watches. 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. Like the mollusc, the Rolex Oyster is robust and clamped shut.
It provides a hermetic environment that protects the high-precision Perpetual movement from water, dust, or pressure.

The name Rolesor was registered in 1933 and today designates the harmonious combination of 18 ct gold and steel on a single watch. Rolex’s first experience with the juxtaposition of two contrasting metals dates back to the 1920s, when Rolex watches were available with a two-tone Bicolore gold case: mostly yellow or red gold paired with white gold or platinum. Three years after the launch of the Oyster Perpetual Datejust in 1945, the model was presented in Rolesor. The use of yellow, Everose, or white Rolesor was gradually extended to other models including watches in the Professional range.

By operating its own exclusive foundry, Rolex has the unrivalled ability to cast the highest quality 18ct gold alloys. According to the proportion of silver, copper, platinum or palladium added, different types of 18ct gold are obtained: yellow, pink or white. They are made with only the purest metals and meticulously inspected in an in-house laboratory with state-of-the-art equipment, before the gold is formed and shaped with same painstaking attention to quality. Rolex's commitment to excellence begins at the source.

The Triplock winding crown is a patented triple waterproofness system designed especially for divers’ watches. Developed by Rolex, it resists water pressure to depths of 300 metres (1,000 feet) on the Submariner models and some other Professional models, and 3,900 metres (12,800 feet) on the Rolex Deepsea. First introduced in 1970, the Triplock system consists of 10 different elements crafted from the most reliable materials. The winding crown screws down against the Oyster case as tightly and hermetically as a submarine’s hatch.

The Cyclops lens enhances the date aperture, magnifying the date display by two and a half times for easy reading. It is one of the most distinctive Rolex features, and one of the most recognizable.

The watch case is rigorously tested to ensure it meets pressure-resistance requirements. The three-step process - a vacuum test, a compression test and a condensation test - will reveal the presence of even the smallest amount of moisture inside the case.

The Submariner Date is equipped with calibre 3135, a self-winding mechanical movement entirely developed and manufactured by Rolex. Like all Rolex Perpetual movements, the 3135 is a certified Swiss chronometer, a designation reserved for high-precision watches that have successfully passed the Swiss Official Chronometer Testing Institute (COSC) tests. It is fitted with a Parachrom hairspring, offering greater resistance to shocks and to temperature variations. Its architecture, in common with all Oyster watch movements, makes it singularly reliable.

The four simple words Superlative Chronometer Officially Certified on a Rolex watch dial mean that the very movement inside the timepiece has endured 15 days and nights of testing by COSC (Contrôle Officiel Suisse des Chronomètres – Swiss Official Chronometer Testing Institute), an independent not-for-profit association. To receive COSC certification as a Swiss chronometer, a watch must demonstrate extreme precision in a variety of positions and temperatures. Rolex is unique in the industry: this is the standard level of quality required of every Rolex wristwatch movement.

In a mechanical watch, the oscillator is the guardian of time. Conventional oscillator hairsprings are made of ferromagnetic alloys, leaving them vulnerable to magnetic fields, temperature variations and shocks that interfere with their precision. After years of research, Rolex created the blue Parachrom hairspring, which is finer than a human hair. Crafted from a highly stable paramagnetic alloy that includes niobium and zirconium, it is insensitive to magnetic fields and up to 10 times more resistant to shocks. Historically, the unique blue colour of the hairspring has been a sign of prestige reserved for only the most accurate timepieces.

Invented by Rolex in 1931, this ingenious mechanism harnesses the energy of natural wrist movements to provide a reliable and clean source of power for the watch movement. It consists of a half-moon- shaped oscillating weight, which pivots freely in both directions on its axle. As it rotates, the rotor continuously winds the Perpetual movement’s mainspring, ensuring a constant and stable source of energy. This enhances the watch’s precision and eliminates the need to wind it regularly. The Perpetual rotor mechanism features two distinctive red reversing wheels, which ensure efficient winding of the movement regardless of the direction in which the oscillating weight rotates.

The name Rolesor was registered in 1933 and today designates the harmonious combination of 18 ct gold and steel on a single watch. Rolex’s first experience with the juxtaposition of two contrasting metals dates back to the 1920s, when Rolex watches were available with a two-tone Bicolore gold case: mostly yellow or red gold paired with white gold or platinum. Three years after the launch of the Oyster Perpetual Datejust in 1945, the model was presented in Rolesor. The use of yellow, Everose, or white Rolesor was gradually extended to other models including watches in the Professional range.