Patek Philippe Perpetual Calendar Chronograph 3970EJ-014

'Fourth Series', Reference 3970EJ-014 | A yellow gold perpetual calendar chronograph wristwatch with moon phases, leap year and 24-hour indication | Circa 2004 Patek Philippe

Dial: silvered Calibre: cal. 27-70 Q manual winding, 24 jewels Movement number: 3'047'196 Case: 18k yellow gold, screw-down sapphire crystal display case back Case number: 4'253'538 Closure: 18k yellow gold Patek Philippe folding clasp Size: 36.2 mm diameter Signed: case, dial and movement Box: yes Papers: yes Accessories: Patek Philippe Certificate of Origin, instruction manual, leather bifold, setting pin, 18k yellow gold solid case back and presentation case with outer packaging Please note the leather strap derived from endangered species is for display purposes only and is not sold with the watch. The watch will be shipped with a Sotheby’s branded calf leather strap.Launched in 1986, the reference 3970 was Patek Philippe’s third perpetual calendar chronograph made in series. Powered by the Lemania 2310 as its base, the caliber CH 27-70Q was heavily modified by Patek Philippe. The reference 3970 was the first perpetual calendar chronograph made by the firm to indicate the leap years. The first series of the 3970 featured a solid snap-on case back. It was later replaced with Ref. 3970E like the current example, which features an updated screw-down case back, with the suffix indicating étanche , or waterproof. This screw back case back was produced for the second to fourth series of the model until the Reference 3970 ceased production 2004. The reference was a complete success and was kept it in production for almost twenty years, making it in yellow, pink and white gold, and in platinum. The present example, from the last year of production of the reference, comes as a full set with its Certificate of Origin, presentation case, second case back and setting pin.