The Patek Philippe Reference 3970 marked a milestone as the brand’s first perpetual calendar chronograph to feature both a leap year indicator and a 24-hour display. Interestingly, despite its added complexity, the 3970 introduced a reduction in case size for the perpetual calendar chronograph line, shifting from 37.5mm to a more compact 36mm.
The Patek Philippe Reference 3970 marked a milestone as the brand’s first perpetual calendar chronograph to feature both a leap year indicator and a 24-hour display. Interestingly, despite its added complexity, the 3970 introduced a reduction in case size for the perpetual calendar chronograph line, shifting from 37.5mm to a more compact 36mm.