Swiss patented pocket watch with visible balance Circa 1907

Silver open faced pocket watch by Mathez, Hofstetter & Cie.
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A Swiss gentleman’s patented pocket watch with visible balance, original box and extensive documentation, circa 1907. Silver engine turned case. Peripheral enamel dial with Arabic numerals and blued spade hands. 3/4 plate movement, gilt, engraved, Brevet 39164 (Perfectionnement au mécanisme de remontoir des montres, 1908), Brevet 39278 (Mouvement de montre, 1908), pin lever escapement, monometallic screw balance.
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Diameter: 50 mm
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Weight: 80 g
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Signed: Mathez, Hofstetter & Cie. à Tramelan