Patek Philippe caliber 31-505 8J PS IRM CI J

The manually wound caliber 31-505 8J PS IRM CI J integrates traditional watchmaking techniques with notable technical advancements. It features the Pulsomax® escapement, equipped with an escape wheel and lever made from Silinvar®, originally developed by the Patek Philippe Advanced Research program. Two series-coupled barrels provide a power reserve of eight days, maintaining consistent accuracy. A ninth "reserve" day, indicated in red on the curved power-reserve display at 12 o'clock, alerts the user to wind the movement. The caliber also includes an instantaneous day-date mechanism that jumps precisely at midnight. Patek Philippe Caliber Ref. 31-505 31-505 8J PS IRM CI J Instantaneous date by hand. Instantaneous day in an aperture. Power reserve indication. Small seconds. Diameter: 32 mm. Thickness: 5.05 mm. Number of parts: 256. Frequency: 28,800 semi-oscillations/hour (4 Hz). Power reserve: min. 192 hours (8 days). Escapement: Pulsomax®.