PATEK PHILIPPE PERPETUAL CALENDAR Ref. 5159G-001
Patek Philippe Perpetual Calendar white gold material. Sapphire-crystal case back protected by a hinged dust cover. Strap: matte dark brown alligator. Fold-over clasp. Self-winding mechanical movement. Caliber 324 S QR. Day, month, leap year in apertures. Sweep seconds hand. Water resistant to 30 m.
In order to accommodate months with 31, 30 and 28 days, and February 29 in leap years, a movement must have a mechanical “memory” of four years – or 1,461 days. This function requires a highly sophisticated mechanism, based on a complex system of levers and cams pivoting around their axes. This is a domain in which Patek Philippe has repeatedly leveraged its long-standing competence.