The Cortebert 677C is a mechanical watch movement that was introduced in 1979. It is an open face calibre with a Breguet hairspring, which contributes to its accurate timekeeping capabilities. The movement features adjustment screws on the balance spokes, allowing for precise regulation. The Cortebert 677C movement offers functions such as stem winding and setting, as well as a sub-second display. Its period of usage spans from 1979 onwards.