The Fontainemelon 90 is a manual wind mechanical watch movement that features a ratchet on the dial side and a crown mechanism with a rocker bar. Variants with less than 15 jewels utilize metal bushings instead of jewels. The movement often or always includes a signature on the dial side with the number 100. It offers several functions such as sweep seconds, calendar with the ability to set the date by changing the hours from 21:50 to 24:00.