| Bezel | Domed |
| Bracelet | Jubilee, five-piece links |
| Bracelet Material | Oystersteel |
| Calibre | 2236, Manufacture Rolex |
| Certification | Superlative Chronometer (COSC + Rolex certification after casing) |
| Clasp | Concealed folding Crownclasp |
| CollectionName | Datejust |
| Crystal | Scratch-resistant sapphire, Cyclops lens over the date |
| Dial | Bright blue |
| Diameter | 31 mm |
| Material | Oystersteel |
| Model Case | Oyster, 31 mm, Oystersteel |
| Movement | Perpetual, mechanical, self-winding |
| Power Reserve | Approximately 55 hours |
| Reference / Code | 278240 |
| Water Resistance | Waterproof to 100 metres / 330 feet |
| Winding Crown | Screw-down, Twinlock double waterproofness system |
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.
