Measuring 31 mm across its round Oystersteel case, this Datejust 31 is built around Rolex's Oyster architecture — a monobloc middle case, screw-down case back, and a screw-down Twinlock winding crown that together deliver water resistance to 100 metres. A scratch-resistant sapphire crystal with a Cyclops lens over the date window sits above the dark grey dial, which is marked with Roman numerals and finished with a domed bezel.
The Oystersteel Jubilee bracelet features five-piece links and fastens with a concealed folding Crownclasp, lending the piece its distinctively refined wrist presence. Inside, the Calibre 2236 — a perpetual, mechanical, self-winding movement from Manufacture Rolex — offers a power reserve of approximately 55 hours, a precision rating of -2/+2 seconds per day after casing, and a Syloxi silicon hairspring with Paraflex shock absorbers. Stop-seconds functionality allows for precise time setting.
The movement holds Superlative Chronometer status, reflecting both COSC certification and Rolex's own post-casing testing standards. Reference 278240-0016 is catalogued under the Datejust 31 family and represents the model in Oystersteel with this dark grey Roman dial configuration.
