Extremely rare Swiss split seconds chronograph Circa 1952

Chronograph with vertically positioned subsidiary dials by Patek Philippe
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An extremely fine and rare Swiss 18 carat gold open faced split seconds chronograph keyless lever watch with vertically positioned subsidiary dials and box, circa 1952. Nickel finished lever movement, 25 jewels, bimetallic compensation balance, micrometer regulator. Silvered matte dial, applied gold baton and Arabic numerals, outer Arabic five minute divisions and tachymetre scale, two vertically positioned subsidiary dials for 30 minutes register and constant seconds. Plain case, stepped bezel, snap on back with stepped rim, chronograph mechanism operated through the crown and two rectangular buttons in the band. Case, dial and movement signed.
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Diameter: 46 mm
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Signed: Patek Philippe Genève