French gold Louis XVI style pocket chronometer Circa 1870

Gold open faced chronometer by Maingourd Frères
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A very fine and rare French 18 carat gold open faced Louis XVI style pocket chronometer, circa 1870. Chronometer movement, ¾ main plate, chain/fusee, extravagant fine adjusting device, helical hairspring, screwed gold chatons, balanced lever, very rare malteser mechanism disengaging and protecting the chain of getting more wound up by crown. White enamel Louis XVI dial with black Roman hours and red five minutes, rose gold hands. Louis XVI case with curved lateral hinge, the back monogrammed AG. Comes with the original box.
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Diameter: 47 mm
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Weight: 90 g
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Signed: Maingourd Frères Le Mans