Superlative waterproofness


Developed for professional saturation diving and extended deep-sea missions, the Sea‑Dweller combines a number of technical innovations to guarantee enhanced waterproofness, robustness through and through, optimum legibility and comfort in all circumstances.

Helium valve

Helium escape valve
Mastering pressure

The helium escape valve, which is exclusive to Rolex and was patented in 1967, the year the Sea‑Dweller was launched, is an intrinsic feature of the model and a major invention for saturation diving. It is screwed to the case and consists of a hermetic cylinder, a piston, a gasket and a spring, acting as a safety valve in case of excess internal pressure.

During descent, the hyperbaric chamber is filled with a mixture of gases, composed primarily of helium, which is vital for the diver’s survival. The helium molecules are so small that they penetrate the watch case. During the decompression process, if the helium does not escape fairly rapidly, it can damage the watch, even separating the crystal from the case under the effects of expansion.

The helium escape valve is unidirectional and is automatically activated when the pressure inside the case is greater than the external pressure. It releases the helium atoms, therefore preserving the integrity of the watch during the return to the surface.

Graduated bezel
Legibility and security on the wrist

A key feature of the Sea‑Dweller and all Rolex divers’ watches, the unidirectional rotatable bezel is fitted with a 60-minute graduated monobloc Cerachrom bezel insert. This vital divers’ tool measures immersion time with precision.

Manufactured by Rolex and patented, the Cerachrom bezel insert is made of high-technology ceramic. It is extremely hard, virtually scratchproof, and its colour is inalterable. The moulded, recessed graduations and numerals are coated with contrasting platinum or yellow gold via PVD (Physical Vapour Deposition).

The bezel can also be turned with ease, even when wearing gloves, thanks to a knurled edge that offers excellent grip.

Triplock crown

Triplock crown
Reinforced waterproofness

Now waterproof to 1,220 metres (4,000 feet), the Sea‑Dweller is fitted with a Triplock winding crown that reinforces the impermeability of its 43 mm Oyster case. This screw-down crown was invented in 1970 and comprises three waterproofness zones.

Featured on all Rolex divers' watches, it is composed of around 10 components made from materials selected for their intrinsic properties: polymers for the waterproof seals, Oystersteel, precious metals and RLX titanium for the mechanical and aesthetic parts.

Screwed to the case for perfect waterproofness, the Triplock crown is recognizable by its three raised symbols under the Rolex emblem on the front.

Rolesor Sea-Dweller

Oystersteel and Rolesor
Robustness and luxury


The Sea‑Dweller is available in Oystersteel, a special alloy that belongs to the 904L steel family, most commonly used in high-technology environments, such as in the aerospace and chemical industries.

In 1985, Rolex became the first watchmaking brand to use solid blocks of 904L steel for certain cases.

Oystersteel is extremely corrosion-resistant and gives the Sea‑Dweller a unique radiance, which retains its lustre even when the watch is put to extreme use.


The Sea‑Dweller is also available in a yellow Rolesor version. For nearly a century, gold and steel have been combined at Rolex in a duet where refinement meets robustness.

Rolesor, whose name was registered in 1933, is exclusive to Rolex watches in the Oyster Perpetual collection. The concept is simple: the bezel, the winding crown and the centre bracelet links are made of yellow or Everose gold, while the middle case and the outer links of the bracelet are made of Oystersteel. On white Rolesor models, the bezel alone is in white gold. These unique combinations are a brand signature.


Chromalight display
The power of the blue glow

The Chromalight display gives the Sea‑Dweller optimal legibility in any circumstances. The luminescent material used is a brilliant white in daylight and emits an intense blue glow in the dark.

Exclusive to Rolex and introduced in 2008, the Chromalight display was optimized in 2021 with the use of a new substance that emits a longer-lasting blue emission intensity and an even brighter white hue in daylight. The performance of this luminescent material clearly exceeds the standards required by watchmaking norms.

The result of a complex manufacturing process, this material is obtained by firing an ultra-fine powder – composed of aluminium, strontium, dysprosium and europium – at a high temperature and then mixing it with liquid resin. The hour markers, hands, capsule and bezel are filled or covered by hand. This operation requires great precision in order to perfectly dose the quantity of material and obtain a uniform result that meets Rolex’s criteria of excellence.

Rolex savoir-faire
Serving divers

Cyclops lens

Since its creation in 1967, the Sea‑Dweller has displayed the date in a window: a vital feature for divers on extended underwater missions lasting up to several dozen days.

Updated in 2017 for its 50th anniversary, the Sea‑Dweller has since been fitted with a Cyclops lens on its sapphire crystal. Designed to improve the readability of the date thanks to its magnifying effect, the Cyclops lens is both an aesthetic and technical signature of the brand. This Rolex invention, named after the one-eyed giant of Greek mythology, was patented in the early 1950s and first introduced in 1953.

Like the watch crystal, the Cyclops lens is made of sapphire, a virtually scratchproof material whose qualities are enhanced by a double anti-reflective coating.


The Oyster bracelet on the Sea‑Dweller is fitted with a patented Oysterlock safety clasp. It also presents a Rolex Glidelock extension system developed by Rolex, which allows the watch to be worn comfortably over a diving suit.

Reserved for Rolex Professional watches, the Oysterlock clasp is synonymous with cutting-edge technology. It features a folding clasp mechanism and a safety catch that prevents accidental opening. It guarantees both reliable fastening and comfortable handling, including underwater.

Integrated into the Oysterlock is the Rolex Glidelock extension system, a sophisticated device consisting of a rack that allows the length of the bracelet to be finely adjusted without the need for tools. The Rolex Glidelock on the Oyster bracelet has 10 notches of approximately 2 mm each.

Calibre 3235

Since 2017, the Sea‑Dweller has been equipped with a 43 mm case and calibre 3235, a self-winding movement entirely developed and manufactured by Rolex. Its architecture, manufacturing and innovative features make it exceptionally precise and reliable.

With 14 patents at the time of its launch in 2015, calibre 3235 is a movement fitted with the Parachrom hairspring and the Chronergy escapement, both of which are resistant to strong magnetic fields. It also boasts Paraflex shock absorbers, which protect the oscillator from impact.

The Sea‑Dweller is a certified Superlative Chronometer that offers excellent performance, particularly in terms of precision (-2/+2 seconds a day) and autonomy (approximately 70 hours).