Swiss gold open faced split seconds chronograph Circa 1916

Gold split seconds chronograph by Patek Philippe
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A fine and rare Swiss 18 carat gold open faced split seconds chronograph keyless lever watch, circa 1916. Retailed by Shreve, Crump & Low Co., Boston. Nickel finished lever movement, 40 jewels, bi- metallic compensation balance, micrometer regulator. Gold cuvette engraved: Made for Shreve, Crump & Low Co. Boston and G.B.M. from F.G.L. July 2, 1929. Silvered dial, Breguet numerals, outer railway five minute divisions, two subsidiary dials for 30 minutes register and constant seconds. Plain case, hinged back with engraved initials GBM, hidden hinges, split seconds chronograph mechanism operated through a button in the band and through the crown, crown locking lever in the band. Case, dial and movement signed by maker, cuvette signed by maker and retailer.
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Diameter: 46 mm
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Signed: Patek, Philippe & Cie Geneva – Switzerland