What is the difference between Patek 3970 and 3940?
The 3970 is outfitted with a manually-wound movement, versus the automatic mechanism of the 3940. Outfitting a perpetual calendar chronograph with an automatic calibre would obscure the beauty of a manually-wound chronograph movement, so it’s good for us watch lovers that they went the hand-wound route. The 3970 model was produced from 1986 to 2004 and combines a perpetual calendar with a chronograph complication. This timepiece illustrates the Geneva-based company’s watchmaking expertise and is part of the brand’s legacy.The serial number, however, stands as the most crucial identifier for a Patek Philippe. This unique number is tied to the entire timepiece, offering a window into its production date and overall history. It serves as the key to unlocking the watch’s authenticity, age, and provenance.Patek Philippe Encased in a refined and classical 33mm case, the 3979 was produced until approximately 2002 and represents one of the earliest wristwatches in the modern era to feature a minute repeater.Patek Philippe’s perpetual calendar chronograph lineage and features a familiar three-register layout: 3 o’clock: Leap year indicator and 30-minute chronograph register. Moon phase and date. Running seconds and 24-hour indicator.