At 31 mm, the Datejust 31 wears the White Rolesor construction that blends Oystersteel with white gold throughout the case. The bezel is set with diamonds, while the dark grey dial features diamonds set in 18 kt gold settings alongside Roman numeral hour markers. A scratch-resistant sapphire crystal with a Cyclops lens magnifies the instantaneous date display, and the screw-down crown employs a Twinlock double waterproofness system for water resistance to 100 metres / 330 feet.
Power comes from the Calibre 2236, a perpetual mechanical self-winding movement produced by Rolex. The oscillator uses a Syloxi hairspring in silicon with patented geometry alongside high-performance Paraflex shock absorbers, delivering a precision of -2/+2 seconds per day after casing and a power reserve of approximately 55 hours via bidirectional winding through a Perpetual rotor. Functions include centre hour, minute, and seconds hands, instantaneous date with rapid setting, and stop-seconds for precise time setting. The movement is COSC certified.
The Oyster bracelet is composed of three-piece solid links in Oystersteel and secures with a folding Oysterclasp featuring an Easylink 5 mm comfort extension link. The case architecture features a monobloc middle case with a screw-down solid case back, maintaining the clean, closed-back profile characteristic of the Datejust line. Reference 278384RBR-0009.
