THE OYSTER CASE, SYMBOL OF WATERPROOFNESS
A paragon of robustness and elegance, the Oyster case of the Datejust 31 is guaranteed waterproof to a depth of 100 metres (330 feet). Its middle case is crafted from a solid block of Oystersteel, a particularly corrosion-resistant alloy. The case back, edged with fine fluting, is hermetically screwed down with a special tool that allows only Rolex watchmakers to access
the movement. The Twinlock winding crown, fitted with a double waterproofness system, screws down securely against the case. The crystal is made of virtually scratchproof sapphire and is fitted with a Cyclops lens at 3 o’clock for easy reading of the date. The waterproof Oyster case provides optimum protection for the watch’s movement.
PERPETUAL CALIBRE 2236
The new versions of the Datejust 31 are equipped with calibre 2236, a movement entirely developed and manufactured by Rolex. At the forefront of watchmaking technology, this self-winding mechanical movement led to the filing of several patents, and offers fundamental gains in terms of precision, power reserve, resistance to shocks and magnetic fields, convenience and reliability.
Calibre 2236 is fitted with a Syloxi hairspring, patented and produced by Rolex. This silicon hairspring remains up to 10 times more precise than a traditional hairspring in case of shocks, and its patented geometry ensures the calibre’s regularity in any position. The movement also contains a paramagnetic nickel-phosphorus escape wheel. The oscillator is fitted on the Rolex-designed and patented high-performance Paraflex shock absorbers, increasing the movement’s shock resistance.
Calibre 2236 is equipped with a self-winding module via a Perpetual rotor and offers a power reserve of approximately 55 hours.