Audemars Piguet Perpetual Calendar

Audemars Piguet's Royal Oak Perpetual Calendar 26674SG.OO.1320SG.01 measures 41 mm across in 18-carat sand gold, a rose-gold alloy, with a case thickness of 4.1 mm. The champagne dial sits under a sapphire crystal. Inside is the self-winding Calibre 7138, a perpetual calendar movement with weekday, date, month and moon phase functions, all adjustable via the crown. This reference is part of a wider line of perpetual calendar watches, and the astronomical moon display is accurate over a long cycle without correction. The bracelet is integrated and made entirely of the same sand gold, closed with an AP folding clasp. Water resistance is rated to 50 metres.