THE INSTANTANEOUS DATE
Rolex uses Oystersteel for its steel watch cases. Specially developed by the brand, Oystersteel belongs to the 904L steel family, alloys most commonly used in high-technology and in the aerospace and chemical industries, where maximum resistance to corrosion is essential. Oystersteel is extremely resistant, offers an exceptional finish once polished and maintains its beauty even in the harshest environments.
The Datejust 31 is equipped with caliber 2235, a self-winding mechanical movement entirely developed and manufactured by Rolex. Like all Rolex Perpetual movements, 2235 is a certified Swiss chronometer, a designation reserved for high-precision watches that have successfully passed the Swiss Official Chronometer Testing Institute (COSC) tests. Its architecture, in common with all Oyster watch movements, makes it singularly reliable.
THE CYCLOPS LENS
The Cyclops lens enhances the date aperture, magnifying the date display for easy reading. It is one of the most distinctive Rolex features, and one of the most recognizable.