The Fleurier 35 watch movement, used from 1964 onwards, features a manual winding mechanism and a sweep second function. In later samples, the setting lever is equipped with a pin instead of a screw, and the minute wheel is also fitted with a pin. These parts can be interchanged with older samples by removing the minute-wheel pin from the plate and utilizing a modified setting-lever spring. The movement is commonly identified by the signature "Bifora 91" or "91/1."