French platinum, Onyx enamel open faced watch Circa 1920

Platinum and Onyx enamel watch by Cartier
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An onyx enamel and platinum open faced watch, circa 1920. European Watch & Clock Co., Inc. manual winding movement, jewelled, cut bi metallic compensation balance, precision snail regulation, silvered guilloché dial, painted black Arabic minute markers, blued steel hands, minute divisions, onyx case, yellow gold and white enamel bezel with radial Roman hour markers, platinum case band, crown, and bow, dial signed Cartier, movement signed European Watch & Clock Co., Inc., with an associated white gold chain.
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Diameter: 49.5 mm
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Signed: Cartier/European Watch & Clock Co., Inc.