CERACHROM BEZEL INSERT
The unidirectional rotatable bezel of the Sea-Dweller is fitted with a 60-minute graduated monobloc Cerachrom insert in black ceramic that allows divers to monitor their time underwater. This insert is made of an extremely hard, virtually scratchproof ceramic whose colour is unaffected by ultraviolet rays. In addition, thanks to its chemical composition, the high-tech ceramic is inert and cannot corrode. The moulded, recessed graduations and numerals are coated with yellow gold or platinum using a PVD (Physical Vapour Deposition) process. The bezel’s knurled edge offers excellent grip, to comfortably set dive time even when wearing gloves.

LEGIBLE AND FUNCTIONAL
In the underwater depths, being able to read the time with absolute certainty is a matter of survival. Great attention was paid to the legibility of the Sea-Dweller: the dial of this professional divers’ watch features a pared-back design and incorporates the Chromalight display. The simple forms of the hour markers – triangles, circles and rectangles – and the hands, which are clearly differentiated in size and shape, are filled or coated with a luminescent material emitting a long-lasting blue glow. On the bezel, the triangular ‘zero’ marker of the graduation is visible in the dark thanks to an embedded capsule containing the same luminescent material.

THE OYSTER CASE, SYMBOL OF WATERPROOFNESS
The Sea-Dweller’s Oyster case, 43 mm in diameter and guaranteed waterproof to a depth of 1,220 metres (4,000 feet), is a paragon of robustness and reliability. The middle case is crafted from a solid block of Oystersteel. The case back, edged with fine fluting, is hermetically screwed down with a special tool employed by approved watchmakers. The Triplock winding crown, fitted with a triple waterproofness system and protected by an integral crown guard, screws down securely against the case. The crystal, with a Cyclops lens at 3 o’clock for easy reading of the date, is made of virtually scratchproof sapphire and benefits from an anti-reflective coating. The waterproof Oyster case provides optimal protection for the movement it houses.

BRACELET AND CLASP: SECURITY AND COMFORT
The Sea-Dweller is fitted on a three-piece link Oyster bracelet. Equipped with a Rolex-designed Oysterlock safety clasp that prevents accidental opening, this bracelet is furnished with the patented Rolex Glidelock extension system, also developed by the brand. On the Oyster bracelet, this inventive toothed mechanism has 10 notches of approximately 2 mm, allowing the bracelet length to be effortlessly adjusted up to some 20 mm. The watch can therefore be worn over a diving suit up to 3 mm thick.

CALIBRE 3235
The Sea-Dweller is equipped with calibre3235, a self-winding mechanical movement entirely developed and manufactured by Rolex. A distillation of technology, this movement carries a number of patents. It offers outstanding performance, particularly in terms of precision, power reserve, convenience and reliability.

Calibre 3235 incorporates the patented Chronergy escapement, made of nickel-phosphorus, which combines high energy efficiency with great dependability and is resistant to strong magnetic fields.

The movement is additionally fitted with the blue Parachrom hairspring. Manufactured in a paramagnetic alloy enabling it to withstand strong magnetic fields, this hairspring also offers great stability in the face of temperature variations as well as high resistance to shocks. It is equipped with a Rolex overcoil, ensuring the calibre’s regularity in any position.

The oscillator of calibre 3235 has a large balance wheel with variable inertia, regulated extremely precisely via gold Microstella nuts. It is held firmly in place by a height-adjustable traversing bridge enabling very stable positioning to increase shock resistance. The oscillator is also mounted on the Rolex-designed, high-performance Paraflex shock absorbers, further enhancing the movement’s shock resistance.

Calibre 3235 is equipped with a self-winding system via a Perpetual rotor, which ensures continuous winding of the mainspring by harnessing the movements of the wrist to provide a constant source of energy. Thanks to its barrel architecture and the escapement’s superior efficiency, the power reserve of this movement extends to approximately 70 hours.

The Sea-Dweller’s movement is beautifully finished and decorated. Since 2023, it has also been marked with the words ‘Chronometer Perpetual’ and ‘Superlative Adjusted’ engraved on the oscillating weight and on the bridges, respectively.

THE SEA-DWELLER, SUPERLATIVE CHRONOMETER CERTIFIED
Like all Rolex watches, the Sea-Dweller is covered by the Superlative Chronometer certification. Symbolized by a green seal, this in-house certification is strictly controlled by internationally recognized, independent Swiss entities. It ensures the excellent on-the-wrist performance of each of the brand’s watches and is coupled with an international five-year guarantee.

In 2026, the Superlative Chronometer certification was expanded to seven testing criteria. Resistance to magnetism, reliability and durability were added to the criteria for precision, waterproofness, self-winding and autonomy, established when the certification was redefined in 2015.

The requirements in terms of precision are particularly stringent. Each Rolex movement is first officially certified as a chronometer. This means that, having passed a series of eliminating tests, it fulfils the criteria governing the ‘chronometer’ designation for wristwatches. For the category of calibres concerned, which includes all Rolex movements, the tolerated rate deviation is –4 and +6 seconds per day.

After casing the movement, the precision is then tested again, following a protocol developed by Rolex that simulates real-life wearing conditions, to meet even stricter criteria: the watch’s accuracy must be between –2 and +2 seconds per day. The rate deviation tolerated by the brand for a finished watch is therefore significantly smaller than that accepted for official certification of the movement alone.