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The Longines Ultra-Chron automatic high-beat-rate wristwatch was introduced in 1967 to mark the 100 year anniversary of the company which was founded in 1867. Longines went on to produce several variations of the Ultra-Chron, including different case shapes, between 1967 and 1975.
High-beat watches were intended to provide greater consistency of rate in different positions and be more isochronous. A number of companies produced such watches, although Girard-Perregaux is said to have been the first to bring these to market in 1965 (showcased at the Basel fair of 1966), with Longines being the second in 1967. Most high-beat watches oscillate at 36,000vph, although 28,800vph was also considered a high rate at the time. To achieve the faster rate, 21 teeth were used in the escape wheel instead of the usual 15. The mainspring was also thicker and larger to provide adequate power. The early GP watches had a relatively short power reserve and many consider that Longines was the first company to release a practical hi-beat watch.
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