Source: Images and content by Rolex. See the original article here - https://newsroom.rolex.com/watches/oyster-collection/lady-datejust
THE OYSTER CASE, SYMBOL OF WATERPROOFNESS
The Lady-Datejust’s Oyster case, 28 mm in diameter and guaranteed waterproof to a depth of 100 metres (330 feet), is a paragon of robustness, proportion and elegance. The middle case is crafted from a solid block of Oystersteel, a particularly corrosion-resistant alloy, or from 18 ct gold. The case back, edged with fine fluting, is hermetically screwed down with a special tool that allows only certified Rolex watchmakers to access the movement. The Twinlock winding crown, fitted with a double waterproofness system, 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. The waterproof Oyster case provides optimum protection for the Lady-Datejust’s movement.
PERPETUAL CALIBRE 2236
The Lady-Datejust is equipped with calibre 2236, a self-winding mechanical movement entirely developed and manufactured by Rolex. A consummate demonstration of technology, this movement carries a number of patents. It offers outstanding performance in terms of precision, power reserve, resistance to shocks and magnetic fields, convenience and reliability.
The oscillator of calibre 2236 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 fitted on high-performance Paraflex shock absorbers, designed and patented by Rolex.
Calibre 2236 incorporates a Syloxi hairspring in silicon, which is patented and manufactured by the brand. Insensitive to magnetic fields, the Syloxi hairspring provides great stability in the face of temperature variations and remains up to 10 times more precise than a traditional hairspring in case of shocks.
The Syloxi hairspring found in calibre 2236 has a geometry that guarantees the regularity of the movement in any position. It also includes a paramagnetic nickel-phosphorus escape wheel.
Calibre 2236 is fitted with a self-winding module via a Perpetual rotor, which ensures continuous winding of the mainspring by harnessing the movements of the wrist to provide constant energy. It offers a power reserve of approximately 55 hours.
The movement of the Lady-Datejust will be seen only by certified Rolex watchmakers, yet it is beautifully finished and decorated in keeping with the brand’s uncompromising quality standards.
OYSTER, JUBILEE AND PRESIDENT BRACELETS
Depending on the version, the Lady-Datejust is available on a three-piece link Oyster bracelet with a folding Oysterclasp; on a five-piece link Jubilee bracelet – created in 1945 especially for the Datejust – with a Crownclasp; or on a three-piece link President bracelet with a Crownclasp. A concealed attachment system ensures seamless visual continuity between the bracelet and case. The Lady-Datejust’s Oyster bracelet also features 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 some 18 ct gold versions, includes ceramic inserts inside the links to enhance its flexibility and longevity.