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.

Silvery-white opaline, gold applied hour markers. Rose gold. Case diameter: 35.1 mm. Thickness: 8.7 mm. Water-resistant to 30 m. Interchangeable solid and sapphire crystal case backs. Straps: shiny alligator with square scales, hand-stitched, mink gray (originally fitted) and royal purple (additional strap). Prong buckle set with 27 diamonds (~0.2 ct). Bezel set with 68 diamonds (~0.68 ct). Prong buckle set with 27 diamonds (~0.2 ct). Perpetual calendar. Moon phases.

Perpetual calendar. Day, date, month, leap year and 24-hour indication by hands. Moon phases. Diameter: 27.5 mm. Thickness: 3.88 mm. Number of parts: 275. Bridges: 8. Jewels: 27. Power reserve: min. 38 hours, max. 48 hours. 22K gold off-center mini-rotor. Balance: Gyromax^®. Vibrations/hour: 21 600 (3 Hz). Balance spring: Spiromax^®. Hallmark: Patek Philippe Seal. Patent: CH 595 653.