Audemars Piguet Perpetual Calendar in 18k yellow gold on leather strap. Auto w/ date, day, month, moonphase and perpetual calendar. Ref B89891. Est. Retail: $35,000; Manufacturer: Audemars Piguet; Model: Perpetual Calendar; Model #: B89891; Materials: 18k Yellow Gold, Leather; Case size: 36 mm; Gender: Male; Dial: White Perpetual Calendar dial; Movement: Automatic; Functions: Date, Day, Month, Moonphase and Perpetual Calendar; Box: Gray & Sons Mahogany Presentation Box; Warranty: 12 months; Condition: Certified pre-owned;.