Swiss gold quality extra chronometer with power reserve Circa 1925

Gold open faced keyless lever pocket chronometer by Patek Philippe & Co.
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A very fine and extremely rare Swiss 18-carat gold open faced keyless lever pocket chronometer with power reserve, Guillaume balance and Bulletin d’Observatoire, circa 1925. Completed and encased in 1929 and sold on 16 January 1930. Nickel finished Extra fully jewelled keyless lever movement numbered twice (manufactured in 1925), Guillaume balance with gold poising screws, micrometer regulator, wolf’s tooth winding. Gold cuvette. White enamel dial with Breguet numerals, two subsidiary dials for power reserve and constant seconds. Engine turned grain d’orge pattern decorated case back. Case, cuvette, movement and dial signed and numbered.
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Diameter: 52 mm
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Weight: 118 g
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Signed: Patek Philippe & Co Genève Chronomètre
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The watch is particularly interesting in that where the banking pins are usually two steel pins embedded in the plate, the task is carried here out by two cut ruby sections that are set in the pallet cock. In 1929, this watch took part in the chronometer test at the Geneva observatory category B and achieved 623 points, which made it 25th of 29 chronometers in this category. It was regulated by F. Modoux. The movement of this watch was encased in 1929 and sold on January 16, 1930.