Rare Swiss stainless steel observation chronometer Circa 1942

Rare steel lever with open-face by Patek Philippe
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An extremely rare Swiss stainless steel observation chronometer Ref. 738, circa 1942.
The anchor chronometer was hallmarked twice with the Geneva seal, 18 jewels, fine adjustment, and manual winding. Silvered dial with Breguet-style radial hours, outer minutes track, subsidiary dial for the seconds, and golden Breguet hands. Brushed steel case. Accompanied by Extract from the Archives confirming the date of sale on June 23rd, 1947. Dial, case and movement signed.
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Diameter: 55 mm
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Weight: 85 g
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Signed: Patek Philippe & Cie Genève