The Citizen 4-280857 watch movement was used from 1968 to 1972 and features a Triovis micrometer regulator. It includes a battery clip that can be secured with a screw on the bridge, allowing for the battery to be held by the back. Initial versions were equipped with a setting-lever screw, but later samples adopted a slide mechanism to release the stem. The movement incorporates several functions, including an electromechanically controlled balance motor, sweep second, day and date display with quickset functionality achieved by repeated pushing of the crown, hack feature to stop the balance, stop seconds functionality, and a calendar.