Swiss silver open faced split second chronograph Circa 1929

Split second chronograph by Ulysse Nardin
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A Swiss silver Ulysse Nardin deck chronometer with four horological complications, including an unusual patented concentric 60-minute and 12-hour recorder, circa 1929. Rhodium-plated, A quality, with going barrel, straight-line lever escapement, Guillaume balance and blued steel hairspring with Phillips terminal curve.
Silver open faced, keyless-winding, round-shaped, deck chronometer, subsidiary seconds at 6 and four horological complications: 1/5 second chronograph (activated by the round push-piece located on the winding crown at 12 o’clock), Split-seconds (activated by the rectangular push-piece located on the case band at 11 o’clock), Dragging 60-minute recorder (subsidiary dial at 12 o’clock), with concentric 12-hour recorder, based on the Swiss invention paten.. 71 222, delivered on June 2, 1915, to John Reymond, Vers-chez-Grosjean, Le Sentier (Vallée de Joux), known as double tour d’heure.
White enamel dial, Roman numerals, two subsidiary dials. Dial, case and movement signed.
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Diameter: 63.5 mm
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Signed: Ulysse Nardin Locle & Genève
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Original fitted box, certificate of origin, Bulletin de Marche and two additional glasses; copies of the invention patent and advertisements; Extract from the Archives.