The Certina 681 watch movement, introduced in 1962, features a micro rotor and double jewel bearing. It incorporates a double excenter regulator for curb pins and stud carrier, and a self-winding gear that utilizes a pinion floating between two large jewels for direction switching. With an indirectly driven minute hand, the movement allows for a low-profile design. The base plate has undergone minor modifications since 1966/67, along with a simplified date driver. The movement functions as an automatic watch, with the date set by changing the 23-24 hour period and, from approximately 1966/67, the 22-24 hour period.