New for 2012 is another outstanding example of Audemars Piguet's tribute to the 40th Anniversary of their iconic Royal Oak model The Royal Oak self-winding watch appears in a new 37 mm 18K rose gold case - adding a feminine dimension to this model. Diamonds enhance & soften the iconic octagonal case in 18K rose gold The aesthetic of its dial is in tune with that of the Royal Oak self-winding 41 mm model (reference 15400), thereby perpetuating the “family likeness 18K rose gold case, glare-proofed sapphire crystal and case back, diamond-set bezel, screw-locked crown 40 brilliant-cut diamonds( 0.90 ct.) on the bezel. Automatic movement - Caliber 3120 - Frequency of balance wheel:3,00 (=21’600 alternances/hour) Direction of automatic winding: Bidirectional Type of oscillating weight: Monobloc in 22K gold Power reserve:60 hours Date / Date in Dial aperture at 3 o'clock Water-resistant to 50 meters / 165 feet.