Longines dips into their archives to revive one of their coolest creations of the ‘60s, the high-frequency Ultra-Chron Diver. The brand’s history with high-frequency movements actually goes back much further, from a 50Hz (!) stopwatch capable of measuring 1/100th of a second in 1916, to classy 5Hz wrist watches in the late 50’s. In 1968 came the Ultra-Chron Diver, complete with a high-frequency caliber 431, with guaranteed accuracy to one minute a month. Today, the Ultra-Chron returns with a 5Hz Longines caliber L836.6, a certified “ultra chronometer” movement running within.
The ultra chronometer badge comes courtesy the independent Swiss testing laboratory, Timelab, who subjects the watch head to 15 days of brutal tests at extreme temperatures to ensure it meets the criteria set forth in ISO 3159:2009 standard. These protocols go well above and beyond the usual chronometer certification, and if the watch makes it through to the other side while retaining -4/+6 seconds accuracy, Longines can call it an Ultra Chronometer. Turn the watch over and you’ll find this proudly emblazoned on the caseback.