The Alpina 689 watch movement was manufactured exclusively for Mido during the period of 1954-1960. It features a base plate derived from the AS 1131/1132 movement, with optional black rhodium plating. The movement offers the choice of a Fonto regulator with a mobile stud carrier and adjustable regulator pin-width, or an Incastar regulator. The Incastar regulator stands out as the only large-scale produced regulator with a free oscillating hairspring, where the end of the spring is secured between two rollers to adjust its length, eliminating isochronism errors caused by the gap between the regulator pins. Additionally, the movement functions with automatic winding and includes a sub-second indication.