Rolex Datejust 31 mm

The Rolex Datejust 31 mm reference 278288RBR-0030 comes in 18 ct yellow gold with a case measuring 31 mm across. A sapphire crystal with a Cyclops lens sits over the date, and the bezel is diamond-set. The dark grey dial is also set with diamonds and pairs with the President bracelet, closed by a concealed folding Crownclasp, both in yellow gold. Inside is the calibre 2236, a perpetual, mechanical, self-winding movement with a power reserve of approximately 55 hours. This is a chronometer, certified to Rolex's Superlative Chronometer standard, and the screw-down crown adds a further layer of protection. The Datejust functions include a central seconds hand and instantaneous date. Rolex rates the case to 100 metres.