Sized at 31mm, the Datejust 31 (ref. 278344RBR-0024) is built around a round White Rolesor case — Rolex's combination of Oystersteel and white gold — featuring a monobloc middle case, solid case back, and a screw-down winding crown with Twinlock double waterproofness. The domed bezel is set with diamonds, while a scratch-resistant sapphire crystal with a Cyclops lens over the date window sits above the dark grey dial dressed with Roman numeral hour markers. Water resistance extends to 100 metres / 330 feet.
Inside runs the Calibre 2236, a perpetual mechanical self-winding movement manufactured by Rolex. It delivers a precision of -2/+2 seconds per day after casing, a power reserve of approximately 55 hours via bidirectional winding through the Perpetual rotor, and features a Syloxi silicon hairspring with patented geometry alongside Paraflex shock absorbers. Functions include centre hour, minute, and seconds hands, an instantaneous date with rapid setting, and stop-seconds for precise time setting. The movement is COSC certified.
The watch rides on a Jubilee bracelet with five-piece links in Oystersteel, fastened by a concealed folding Crownclasp. Reference 278344RBR-0024 brings together diamond ornamentation and a composed dark grey dial in a versatile 31mm format well suited to the Datejust's enduring character.
