The Rolex Datejust 31 in yellow gold is reference 278278. It has a 31mm case made of 18k yellow gold, cast in Rolex's own foundry. The date shows in a window at 3 o'clock under a Cyclops lens. The Datejust introduced the self-winding wristwatch with a date window in 1945.
The champagne dial has diamond hour markers and is surrounded by a fluted 18k yellow gold bezel. The case is paired with a three-piece-link Oyster bracelet.
The watch uses the in-house Rolex caliber 2236, which runs for about 55 hours once fully wound. Every movement of this generation is tested as a Superlative Chronometer, accurate to within -2/+2 seconds a day. The screw-down crown and sapphire crystal keep it water resistant to 100 meters.
- Reference
- 278278
- Case
- 31mm, 18k yellow gold
- Bezel
- Fluted, 18k yellow gold
- Dial
- Champagne, diamond hour markers
- Crystal
- Sapphire, with Cyclops lens over the date
- Bracelet
- Oyster, three-piece links
- Movement
- Rolex caliber 2236, self-winding
- Power reserve
- About 55 hours
- Accuracy
- -2/+2 seconds a day (Superlative Chronometer)
- Functions
- Hours, minutes, seconds, date
- Water resistance
- 100 m / 330 ft