The Zodiac 72B is a mechanical watch movement exclusively produced for Mido during the period of 1954-1960. It features a base plate of the AS 1131/1132 and offers optional black rhodium plating. Additionally, it provides the option of a Fonto regulator with a mobile stud carrier and adjustable regulator pin-width. Notably, it is the only large-scale produced regulator that incorporates a free oscillating hairspring. The spring's end is fixed between two rollers, allowing for adjustment of its length and eliminating any isochronism error caused by the gap between the regulator pins. The movement comprises functions such as automatic winding and a sweep seconds hand.