Swiss gold watch in US 10 Dollar gold coin dated 1906 Circa 1980

Gold keyless lever coin watch 
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A very fine and rare Swiss 10 U.S. Dollar gold coin dated 1906 with concealed watch, circa 1980. Accompanied by the original fitted box. Double case, coin opening with a push-piece concealed in the band, three-body hinged inner case. Gold with painted baton indexes and blued steel baton hands. Rhodium-plated movement, 18 jewels, straight-line lever escapement, monometallic balance, shock absorber, self-compensating flat balance spring. Dial, case and movement signed.
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Thickness: 4 mm
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Diameter: 30 mm
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Signed: Piaget  Swiss