Unusual Swiss silver split-seconds lever chronograph Circa 1921

Silver 30-minute recording split-seconds chronograph
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A Swiss silver open faced 30-minute recording split-seconds chronograph with unusual dial layout, hallmarked London (import) 1921. Gilt three-quarter plate keyless movement with going barrel, plain cock with polished steel regulator, uncut bimetallic balance with overcoil hairspring, club foot lever escapement. Plain silver cuvette. Unusual white enamel dial, split centre seconds flyback chronograph and three subsidiaries for time, continuous seconds and 30-minute record and blue steel hands. Plain silver case with gold hinges, thumb-piece, split-seconds button in the band and gilt winding button for the chronograph. Maker’s mark LW in a rectangle.
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Diameter: 54 mm
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Signed: The Winner