Crafted in Everose Rolesor — Rolex's combination of Oystersteel and Everose gold — the Datejust 31 reference 278381RBR-0017 presents a 31 mm round case with a bezel set with diamonds. The slate dial is fitted with index hour markers and viewed through scratch-resistant sapphire crystal with a Cyclops lens positioned over the date window. The monobloc middle case features a solid case back and a screw-down winding crown with Twinlock double waterproofness, providing water resistance to 100 metres / 330 feet.
The three-piece solid-link Oyster bracelet is rendered in matching Everose Rolesor and secures via a folding Oysterclasp with an Easylink 5 mm comfort extension link. Powering the watch is the perpetual, mechanical, self-winding Caliber 2236 Manufacture Rolex movement, delivering a precision of -2/+2 seconds per day after casing and a power reserve of approximately 55 hours. The oscillator features a Syloxi hairspring in silicon with patented geometry and high-performance Paraflex shock absorbers, while bidirectional self-winding is achieved via a Perpetual rotor.
Functions include centre hour, minute, and seconds hands alongside an instantaneous date with rapid setting and stop-seconds for precise time adjustment. The movement is COSC certified, and the date complication is the sole additional indication on this classically proportioned 31 mm Datejust.
