French gunmetal indirect centre seconds keyless lever Circa 1910

Gunmetal open faced decimal day and night watch
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A fine and unusual French gunmetal open faced indirect centre second keyless lever pocket watch, circa 1910. White enamel dial with black Arabic decimal hours, an outer minute track and central blue four times of the day and night indication. Polished case. Dial signed, case numbered.
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Diameter: 54 mm
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Signed: Décimale Métrique Leroy Paris