Heritage Ultra-Chron Classic 40mm Automatic

From the retailer listing

Revisiting a classic, high-frequency pioneer In 1968, Longines launched the Ultra-Chron Diver, the first dive watch equipped with a high-frequency movement. At the time, Longines had already established itself as a pioneer in high-frequency technology. As early as 1910, the winged hourglass brand created the first high-frequency timekeeping device capable of measuring 1/10th of a second. In 1959, Longines developed the first high-beat movement for a wristwatch, an observatory chronometer that set new records in terms of accuracy. This new Ultra-Chron is inspired by the aesthetic codes and professional diving features of the 1968 model. This chronometer-certified watch is powered by a Longines-exclusive high-beat calibre equipped with a silicon balance-spring and resistant to magnetic fields.