| Reference | 278240 |
| Material | Oystersteel |
| Diameter | 31 mm |
| Movement | Perpetual, mechanical, self-winding |
| Dial | Bright blue |
| Power Reserve | Approximately 55 hours |
| Model Case | Oyster, 31 mm, Oystersteel |
| Bezel | Domed |
| Winding crown | Screw-down, Twinlock double waterproofness system |
| Crystal | Scratch-resistant sapphire, Cyclops lens over the date |
| Water resistance | Waterproof to 100 metres / 330 feet |
| Calibre | 2236, Manufacture Rolex |
| Bracelet | Jubilee, five-piece links |
| Bracelet Material | Oystersteel |
| Clasp | Concealed folding Crownclasp |
| Certification | Superlative Chronometer (COSC + Rolex certification after casing) |
Bright blue dial
The sunray finish creates delicate light reflections on many dials in the Oyster Perpetual collection. It is obtained using masterful brushing techniques that create grooves running outwards from the centre of the dial. Light is diffused consistently along each engraving, creating a characteristic subtle glow that moves depending on the position of the wrist. Once the sunray finish has been completed, the dial colour is applied using Physical Vapour Deposition or electroplating. A light coat of varnish gives the dial its final look.
Oystersteel
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 Jubilee bracelet
The design, development and production of Rolex bracelets and clasps, as well as the stringent tests they face, involve advanced high technology. And, as with all the components of the watch, aesthetic controls by the human eye guarantee impeccable beauty. The Jubilee, a supple and comfortable five-piece link metal bracelet, was designed and made especially for the launch of the Oyster Perpetual Datejust in 1945.Model Availability
