Case material: Rose gold; Charge: Manual; Conditions: Used Year : 1992; Presentation condition : With dealer guarantee ; Price on request Gmtbroker Reference: 3790E An 18k  Rose Gold Perpetual Calendar Chronograph Gents Wristwatch, opaline  silver dial with applied hour markers, 30 minute recorder and leap year indicator at 3 0'clock , date sub-dial and moonphase  aperture at 6 0'clock , small seconds and 24 hour sub-dial at 9 0'clock , day and month apertures at 12 0'clock , a fixed 18k rose gold bezel, an original navy blue leather strap with an original 18k rose gold pin buckle, sapphire glass, exhibition caseback , additional 18k rose gold caseback ,  manual wind movement, in excellent condition, comes complete with a Patek  Philippe box and Papers Dated December 1992. N.B. Since its initial introduction in 1986 to its end in 2004, there have been 3 series of the 3970: First series:  An estimated run of only 100 watches, all in 18k yellow gold. It featured leaf shaped hands, applied hour markers, sub-dials that were slightly off colour and a snap caseback.  This series is considered extremely rare. Second series:  Produced approximately between 1987 to 1990, there are two variations to this series;  The first variation visually look similar to the first series, although the sub-dial were now textured as opposed to a different colour. The main difference was the solid screw caseback, making the watch water resistant.  It was later on, through the request of clients, that a second variation with a sapphire