Swiss 18 Carat gold trip minute repeating keyless lever Circa 1920

Gold repeater built to the design of Swiss patent No. 5128
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A very fine and very rare Swiss 18 Carat gold open faced trip minute repeating keyless pocket watch with single train, built to the design of Swiss patent No. 5128, circa 1920. Rhodium-plated movement, 23 jewels, single large barrel powering both trains, straight-line lever escapement, cut bimetallic compensation balance with blued steel Breguet balance spring, swan neck micrometre regulator, repeating on gongs activated by depressing the button on winding crown. Gold hinged cuvette. White enamel dial with Breguet numerals, outer minute track, subsidiary seconds, and original blued steel spade hands. Polished case, semi concealed hinge. Front plate punched with Swiss Patent No. 5128.
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Diameter: 48 mm
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Signed: No name