The Osco 400 is a mechanical watch movement that was used from 1974 onwards. It features a pin-lever escapement and a dial plate that is fixed on the base movement using dial feet. This movement can be manually wound and is available with or without a sweep second hand. The day function can be set by changing the time between 20:00 and 1:00, while the date function can be set by changing the time between 21:45 and 24:00.