Swiss gold watch set in US 20 Dollar gold coin dated 1907 Circa 1960

Gold lever coin watch by Audemars Piguet
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A very fine Swiss, keyless, 18K yellow gold purse watch, set into a U.S. 20 Dollar coin dated 1907, circa 1960. Accompanied by a fitted box, leather case and certificate. Double case, coin opening with a push-piece concealed in the band, three-body hinged inner case. Matte silver dial with painted baton indexes, blued steel baton hands.
A rhodium-plated movement, Geneva striping decoration, 17 jewels, straight-line lever escapement, monometallic balance adjusted to heat, cold, isochronism and five positions, self-compensating flat balance spring. Dial, case and movement signed.
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Diameter: 35 mm
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Signed: Audemars Piguet  Genève
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The case is slightly scratched.