Swiss open faced World Time lever watch Circa 1951/1963

Gold World Time watch by Patek Philippe
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A very rare and attractive Swiss 18 carat gold open faced World Time keyless lever watch with black dial, circa 1951, completed and encased in 1963. Nickel finished lever movement, 18 jewels, bimetallic compensation balance, swan neck regulator. Black dial, applied gold baton numerals, pierced stylised gold hands, outer silvered ring with the names of 39 world locations, all centred by a revolving grey and white ring calibrated for the Arabic diurnal and nocturnal 24 hours. Plain case, milled bezel, snap on back. Case, dial and movement signed.
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Diameter: 44 mm
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Signed: Patek Philippe Genève