Longines developed their first in-house quartz chronometer (a large rack-mount model) in 1954 and it became the most accurate ever recorded by the Neuchâtel Observatory. The company miniaturized this technology into a pocket chronometer in 1966.
The Ultra-Quartz was the first Swiss quartz watch when it was announced. Called "cybernetic" at the time, it relies on the interaction of two oscillators: A 9,350 Hz quartz crystal is the main timekeeper, while a vibration motor runs slower and actuates the wheel train similar to a tuning fork movement. Each oscillator provides feedback to the other, regulating timekeeping. This is similar to the eventual design of the Bulova Accuquartz of 1971, which would be the first quartz watch sold in the United States.
The Ultra-Quartz does not use an integrated circuits, since Longines did not have this technical capability. Instead, it leverages 30-40 miniature electronic components, a costly and challenging design similar to Seiko's competition chronometers from 1967. The movement was developed in-house at Longines in Saint-Imier, while the company was also participating in the CEH Beta 21 project.
Longines announced the Ultra-Quartz model at a press conference in Geneva on August 20, 1969. This was eight months earlier than the Beta 21 (which also included Longines participation), Omega Megaquartz, Girard-Perregaux Elcron, and Neosonic and 4 months before the Seiko Astron. Longines also showed both Ultra-Quartz and "Quartz-Chron" (Beta 21) watches at the Fair, and sold the two alongside each other through 1971.