INSTANTANEOUS DATE AND CYCLOPS LENS
The Datejust revolutionized wristwatch date display. Traditionally, the days of the month were marked around the edge of the dial, and a hand pointed to the day’s date. With the Datejust, Rolex introduced a calendar that displayed the date via a disc in a window at 3 o’clock. This would become the watchmaking standard. In 1953, the Cyclops lens was added to the crystal, magnifying the date for easy reading. In 1956, the date change became instantaneous.

THE OYSTER CASE, SYMBOL OF WATERPROOFNESS AND ELEGANCE
The Datejust’s Oyster case, 31, 36 or 41 mm in diameter and guaranteed waterproof to a depth of 100 metres (330 feet), is a paragon of robustness and elegance. The middle case is crafted from a solid block of Oystersteel or from 18 ct yellow, white or Everose gold. The case back, edged with fine fluting, is hermetically screwed down with a special tool employed by approved watchmakers. The Twinlock winding crown, fitted with a double waterproofness system, screws down securely against the case. The bezel can be smooth, domed, fluted or set with diamonds. 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.

OYSTER, JUBILEE AND PRESIDENT BRACELETS
The Datejust 31 is available on a three-piece link Oyster bracelet equipped with a Rolex-designed Oysterclasp, or on a five-piece link Jubilee bracelet – created in 1945 especially for the Datejust – or a three-piece link President bracelet, both of which are fitted with a concealed Crownclasp, developed by the brand. The Datejust 36 and the Datejust 41 are available on a three-piece link Oyster bracelet or a five-piece link Jubilee bracelet with an Oysterclasp.

Bracelets equipped with an Oysterclasp feature the Easylink comfort extension link, developed by Rolex, which allows the wearer to easily increase the bracelet length by approximately 5 mm, for additional comfort in any circumstance.

The President bracelet, fitted on all of the 18 ct gold versions (Datejust 31), includes ceramic inserts – designed by Rolex and patented – around the pins inside the links to help prevent premature wear and to enhance its flexibility on the wrist.

CALIBRES 2236 AND 3235
Datejust models are equipped with calibre 2236 (Datejust 31) or calibre 3235 (Datejust 36 and Datejust 41), self-winding mechanical movements entirely developed and manufactured by Rolex. A distillation of technology, these movements carry a number of patents. They offer outstanding performance, particularly in terms of precision, power reserve, convenience and reliability.

Calibre 2236 is fitted with the patented Syloxi hairspring in silicon, manufactured by the brand. In addition to resisting strong magnetic fields, this hairspring offers great stability in the face of temperature variations as well as high resistance to shocks. Its geometry, which is also patented, ensures the movement’s regularity in any position. Calibre 2236 includes a paramagnetic nickel-phosphorus escape wheel.

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. This 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 these two calibres has a 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 movements’ shock resistance.

Calibre 2236 and calibre 3235 are 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 constant energy. Calibre 2236 offers a power reserve of approximately 55 hours, while the power reserve of calibre 3235 extends to approximately 70 hours thanks to its barrel architecture and the escapement’s superior efficiency.

The Datejust’s movements are beautifully finished and decorated. Since 2023, calibre 3235 has also been marked with the words ‘Chronometer Perpetual’ and ‘Superlative Adjusted’ engraved on the oscillating weight and on the bridges, respectively.

THE DATEJUST, SUPERLATIVE CHRONOMETER CERTIFIED
Like all Rolex watches, the Datejust 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.