Swiss 18 carat white gold keyless open faced lever Circa 1955

A Swiss 18 carat white gold keyless wind open faced pocket watch, circa 1955. 18 Jewel Cal.27-AM400 Swiss lever movement, adjusted to heat, cold, isochronism and 5 positions, Seal of Geneva, Gyromax balance. Sunburst silvered dial, applied faceted polished baton hour markers and polished pointed baton hands. Brushed and polished round case, snap on back, crown at 6. Case, dial and movement signed. With Patek Philippe case, Certificate of Identity and Guarantee of Origin and Information booklet.
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Diameter: 40 mm
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Signed: Patek Philippe Genève Swiss