Rolex Datejust 31 mm

Rolex Datejust 31 mm, reference 278240-0015, has a 31 mm steel case with a domed bezel. The dial is dark grey, finished with a sunray effect, and sits under a scratch-resistant sapphire crystal with a Cyclops lens over the date. Inside is calibre 2236, a self-winding movement with a silicon Syloxi hairspring and roughly 55 hours of power reserve. The watch is a chronometer, certified by Rolex after casing, and shows a central seconds display along with the date. A screw-down crown with Twinlock double waterproofness backs up the case. It is fitted to a steel Oyster bracelet with a folding Oysterclasp and Easylink comfort extension link. The Datejust's Oyster case is waterproof to 100 metres.