Unique Swiss gold open faced chronometer watch Circa 1920

Gold lever keyless watch with certificates
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Extremely rare Zenith Observatory Chronometer, “KEW A ESPECIALLY GOOD”, presumably an unique piece, Zenith, circa 1920.
An 18 carat gold, engine-turned, Zenith case punch, chronometer with lever escapement, unusual big golden screwed balance of about Ø18 mm, very unusual and extremely rare fine regulation. Original enamel dial, Breguet-hands, dial with old, fine hairlines, otherwise very nice condition.
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Diameter: 58 mm
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Weight: 148 g
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Signed:  Zenith
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This Zenith Chronometer is one of the rarest and finest pocket watches made by Zenith. The Chronometer was tested four times by competitions from 1921-1924. All certificates are available, including “KEW A 94,2 from 100 points” “Especially good “. We are not aware of any other Zenith-Chronometer of this quality!