| Reference | 278278 |
| Material | 18 ct yellow gold |
| Diameter | 31 mm |
| Movement | Perpetual, mechanical, self-winding |
| Dial | Dark grey set with diamonds |
| Power Reserve | Approximately 55 hours |
| Model Case | Oyster, 31 mm, yellow gold |
| Bezel | Fluted |
| 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 | President, semi-circular three-piece links |
| Bracelet Material | 18 ct yellow gold |
| Clasp | Concealed folding Crownclasp |
| Certification | Superlative Chronometer (COSC + Rolex certification after casing) |
| GEM-SETTING | Large VI set with 11 diamonds |
Dark Grey Dial
This dial features a large VI set with 11 diamonds. 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.
Fluted bezel
The Rolex fluted bezel is a mark of distinction. Originally, the fluting of the Oyster bezel had a functional purpose: it served to screw the bezel onto the case helping to ensure the waterproofness of the watch. It was therefore identical to the fluting on the case back, which was also screwed onto the case for waterproofness, using specific Rolex tools. Over time, the fluting became an aesthetic element, a genuine Rolex signature feature. Today the fluted bezel is a mark of distinction, in gold on this Datejust 31.
18 ct yellow gold
By operating its own exclusive foundry, Rolex has the unrivalled ability to cast the highest quality 18 ct gold alloys. According to the proportion of silver, copper, platinum or palladium added, different types of 18 ct gold are obtained: yellow, pink or white. They are made with only the purest metals and meticulously inspected in an in-house laboratory with state-of-the-art equipment, before the gold is formed and shaped with the same painstaking attention to quality. Rolex's commitment to excellence begins at the source.Model Availability
