PATEK PHILIPPE PERPETUAL CALENDAR CHRONOGRAPH "3rd Series Reference : 3970EJ. Serial number: 2 900 921. 18K (750) yellow gold case. Silver dial, applied hour-markers, chronograph and perpetual calendar function. Hand-wound mechanical movement (CHR -27- 70 Q calibre) No. 876 099, with double back. Leather strap on yellow gold folding clasp, signed. Sapphire crystal. Diameter: 36 mm. Circa 1990. The watch comes with its case and papers. A very fine 18K gold, perpetual calendar, mechanical movement, chronograph wristwatch, by Patek Philippe. Circa 1990. RC: Sold as is, traces of wear and use. Movement functional at the time of writing the description, provide for servicing, without warranty.