Launched in 1986, reference 3970 was PatekPhilippe ’s third perpetual calendar chronograph, but the first to indicate the leap years. Powered by the Lemania 2310 as its base, the calibre CH 27-70Q was heavily modified by the brand. The reference was a complete success and was kept it in production for almost twenty years, produced in all four metals. The Nevadian Collector (25 April | Hong Kong) Lot 2040 | Est. HK$480k – 650k/ US$62k – 83k #SothebysWatches #PatekPhilippe #Patekholic #TheNevadianCollector