Swiss silver watch set into silver coin dated 1870 Circa 1850

Silver Prussian Wilhelm coin watch 
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An extremely rare, silver Prussian Wilhelm I coin dated 1870 fitted with a concealed watch with ultra thin movement, circa 1850. Double coin case, coin opening with a concealed push piece in the band, three body hinged inner case. Silver, florally engraved dial with Roman numerals and blued steel baton hands. Straight line lever escapement, movement is numbered.
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Diameter: 33 mm
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Signed: No Name
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Creating such a slim watch was a remarkable achievement at the time,
very few such watches are known.