Datejust 31
REFERENCE
278240
MODEL CASE
Oyster, 31 mm, Oystersteel
BEZEL
Domed
WATER-RESISTANCE
Waterproof to 100 metres / 330 feet
MOVEMENT
Perpetual, mechanical, self-winding
CALIBRE
2236, Manufacture Rolex
POWER RESERVE
Approximately 55 hours
BRACELET
Oyster, flat three-piece links
DIAL
Silver
CERTIFICATION
Superlative Chronometer (COSC + Rolex certification after casing)
OYSTER ARCHITECTURE
Monobloc middle case, screw-down case back and winding crown
DIAMETER
31 mm
MATERIAL
Oystersteel
WINDING CROWN
Screw-down, Twinlock double waterproofness system
CRYSTAL
Scratch-resistant sapphire, Cyclops lens over the date
PRECISION
-2/+2 sec/day, after casing
OSCILLATOR
Syloxi hairspring in silicon with patented geometry. High-performance Paraflex shock absorbers
WINDING
Bidirectional self-winding via Perpetual rotor
BRACELET MATERIAL
Oystersteel
CLASP
Folding Oysterclasp with Easylink 5 mm comfort extension link
DETAILS
Highly legible Chromalight display with long-lasting blue luminescence


SILVER DIAL
The sunray finish on Rolex dials is a predominant method in watchmaking of achieving pure metallic colour dials such as shades of silver grey, rhodium or ruthenium. Silver-plating is mostly used as a base layer for the sunray finish, where further colour is added to the prepared dial. Sometimes colours such as champagne are achieved through electroplating with more than half a dozen different metals.
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 OYSTER BRACELET
The Oyster bracelet is a perfect alchemy of form and function, aesthetics and technology, designed to be both robust and comfortable. It is equipped with an Oysterclasp and the Easylink comfort extension link, also exclusive to Rolex. This ingenious system allows the wearer to increase the bracelet length by approximately 5 mm, providing additional comfort in any circumstance.

REFERENCE
278240
MODEL CASE
Oyster, 31 mm, Oystersteel
BEZEL
Domed
WATER-RESISTANCE
Waterproof to 100 metres / 330 feet
MOVEMENT
Perpetual, mechanical, self-winding
CALIBRE
2236, Manufacture Rolex
POWER RESERVE
Approximately 55 hours
BRACELET
Oyster, flat three-piece links
DIAL
Silver
CERTIFICATION
Superlative Chronometer (COSC + Rolex certification after casing)
OYSTER ARCHITECTURE
Monobloc middle case, screw-down case back and winding crown
DIAMETER
31 mm
MATERIAL
Oystersteel
WINDING CROWN
Screw-down, Twinlock double waterproofness system
CRYSTAL
Scratch-resistant sapphire, Cyclops lens over the date
PRECISION
-2/+2 sec/day, after casing
OSCILLATOR
Syloxi hairspring in silicon with patented geometry. High-performance Paraflex shock absorbers
WINDING
Bidirectional self-winding via Perpetual rotor
BRACELET MATERIAL
Oystersteel
CLASP
Folding Oysterclasp with Easylink 5 mm comfort extension link
DETAILS
Highly legible Chromalight display with long-lasting blue luminescence

SILVER DIAL
The sunray finish on Rolex dials is a predominant method in watchmaking of achieving pure metallic colour dials such as shades of silver grey, rhodium or ruthenium. Silver-plating is mostly used as a base layer for the sunray finish, where further colour is added to the prepared dial. Sometimes colours such as champagne are achieved through electroplating with more than half a dozen different metals.

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 OYSTER BRACELET
The Oyster bracelet is a perfect alchemy of form and function, aesthetics and technology, designed to be both robust and comfortable. It is equipped with an Oysterclasp and the Easylink comfort extension link, also exclusive to Rolex. This ingenious system allows the wearer to increase the bracelet length by approximately 5 mm, providing additional comfort in any circumstance.