Swiss gold lever chronograph with tachometer Circa 1940

Gold open faced chronograph
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A Swiss 18 carat gold open faced keyless lever chronograph watch with tachometer scale, made by Longines, circa 1940-1945. This watch features a mechanical movement with pendant winding, an anchor escapement, a Breguet balance spring, a straight line, and a column wheel. It has a two tone gilt dial with painted Arabic numerals, a tachometric scale, a 30 minute chrono totaliser at 12 o’clock, a subsidiary dial for seconds at 6 o’clock, a central second hand for the chronograph, and blued steel eventail hands. The plain case is made of 18 carat gold. Dial and movement are signed, with caseback and movement numbered.
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Diameter: 51 mm.
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Weight: 91.5 g
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Signed: Longines