3046. 3046Y Patek Philippe. A very fine and rare 18K gold perpetual calendar manual wind chronograph wristwatch A very fine and rare 18K (750) yellow gold perpetual calendar manual wind chronograph wristwatch. Model: Perpetual Calendar Chronograph Reference: 3970E Date: Purchased 21st July 1992 Movement: 24-jewel Cal.CH27-70Q manual wind, adjusted to temperature, isochronism and positions No.876077 Dial: Third series silvered, applied gilt pointed baton hour markers, black outer minute divisions, subsidiary engine-turned sunken dials at 3, 6, 9 for running seconds with 24 hours recording, 30 minute recording with leap year indicator, date with moonphases, apertures for day and month at 12, gilt pointed baton hands, centre chronograph hand Case: Brushed and polished round, screw down exhibition back, crown flanked by twin pushers, stepped bezel, quick set buttons in the band at 6, 10 and 12, No.2900884 Strap/Bracelet: Patek Philippe black crocodile leather Buckle/Clasp: Signed 18K folding clasp Signed: Case, dial & movement Size: 36mm Weight: 86,84g Accompaniments: Patek Philippe box, outer card, Certificate of Origin dated 21st July 1992, brochures, Instructions manual, additional spare 18K gold case back, quick set tool Reference 3970 was introduced to the market in 1986, and produced through to 2004 when it was replaced by the 5970. Produced in much larger quantities than its predecessors references 2499 and 1518, it nevertheless has enjoyed immense popularity amongst collectors for both the overall design of the watch and for using a Lemania-based movement, the caliber CH 27-70 Q. The reference 3970 was produced in four series, which are as follows: First Series - Produced in 1986 in 100 examples, all cased in yellow gold, with a snap case back. At the same time, the reference 3971 was produced, the difference being a sapphire crystal display snap back on the 3971, while the 3970 back was solid. The hands are known as "leaf hand", and the dials featured baton numerals and subsidiary registers with a slightly different silvered tone than the rest of the dial. Second Series - Produced from 1986 through 1991, the second series differs from the first series in that the subsidiary registers are the same tone as the rest of the dial, and the case back is a solid water-resistant screw down back. At the request of some customers, Patek Philippe would put on a screw back that had a sapphire crystal display. The reference 3971 was also produced with a sapphire crystal display screw back. Third Series - Produced from 1991 through 1996, the third series are also known as a reference 3970E, with the "E" referring to "étanche", which translates to "waterproof". These models came with both a sapphire crystal display screw back, as well as a solid screw back. The third series also featured baton hands, and the baton numerals had pointed tips. Fourth Series - The fourth series is the same as the third series, however it began with a new serial number, starting in 1996 and continuing until production ended in 2004.