The Cortebert 618 watch movement, produced from 1954 to 1966, featured a ratchet on the dial side and a crown mechanism with a rocker bar. It had limited production and was soon replaced by variations of the J93/1 movement. One version of this movement, known as the official version, had 8 jewels, including 1 in the friction spring for the sweep second function. The movement offered manual winding and sweep seconds.