Rare Swiss staybrite stainless steel dress watch Circa 1940

Stainless steel lever by Patek Philippe & Cie
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A rare Swiss staybrite stainless steel keyless dress watch, circa 1940. A silver dial with applied white gold Breguet numerals, outer minute track, subsidiary seconds dial and white gold feuille hands. A gilt brass movement, 18 jewels, straight-line lever escapement cut bimetallic compensation balance, blued steel Breguet balance spring, and an index regulator. Dial, case and movement signed.
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Thickness: 12 mm
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Diameter: 50 mm
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Signed: Patek Philippe & Cie  Genève
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Accompanied by a pouch.