The Fontainemelon 909 watch movement, in production from 1957 to 1962, was the first family of movements to feature a micro rotor for self-winding. The self-winding gear mechanism incorporates a pinion that floats between two large jewels to enable direction switching. In 17-jewel variations, one of these jewels is replaced by a polished steel disc. The movement offers a range of functions including automatic winding, sweep seconds, and a calendar with a date set by changing the time from 23:30 to 24:00 hours.