At 31 mm, the Datejust 31 houses its round Oystersteel case around a pink dial marked with Roman numeral hour indicators. Scratch-resistant sapphire crystal sits above the dial, complete with a Cyclops lens magnifying the date, while the domed bezel frames the presentation with quiet restraint. The monobloc middle case pairs with a screw-down case back and a screw-down Twinlock winding crown, delivering water resistance to 100 metres / 330 feet.
The three-piece solid-link Oyster bracelet is crafted in Oystersteel and secured by a folding Oysterclasp fitted with an Easylink 5 mm comfort extension link. Inside, Calibre 2236 — a perpetual, mechanical, self-winding movement from Manufacture Rolex — drives centre hour, minute, and seconds hands alongside an instantaneous date with rapid setting and stop-seconds for precise time setting. A Syloxi silicon hairspring with patented geometry and Paraflex shock absorbers contribute to a precision rating of -2/+2 seconds per day after casing, with a power reserve of approximately 55 hours.
The movement holds Superlative Chronometer certification, reflecting both COSC testing and Rolex's own certification standard applied after casing. Reference 278240-0013 is a study in understated, well-engineered watchmaking dressed in a softly toned pink dial.
