The Certina 19-55 watch movement, produced from 1957 to 1962, belongs to the first movement family with a micro rotor. Its selfwinding gear incorporates a pinion floating between two large jewels to enable direction switching. In 17-jewels variants, one of these jewels is replaced by a polished steel disc. This movement offers several functions, including automatic winding and a sweep seconds hand. It also features a date function, which can be set by changing the time between 23:30 and 24:00 hours.