The Ebauches SA 9154 watch movement, used from 1969 onwards, features a non-self-starting mechanism, requiring the balance to be locked in position during crown pulling. The am/pm display is indicated by a dot located below or above the date numeral. Setting the hands back and forth advances the date half a day, enabling date adjustments at noon and midnight with attention to the dot's correct positioning. Additional functions include an electromechanically controlled balance motor, back crown, jumping sweep second, date adjustment by changing 22:30-24h, and electrical and mechanical hack feature.