The Unitas 172 is a lesser-known manual-wind version of the 0917 movement, which was specifically developed for Mido and utilizes the AS 1131/1132 base plate. Noteworthy features of this movement include a gold lever and the option of an Incastar regulator. The Incastar regulator is a unique large-scale produced regulator that incorporates a free oscillating hairspring fixed between two rollers to adjust its length and eliminate isochronism errors caused by the gap between regulator pins. The Unitas 172 movement also includes functions such as manual winding and a sweep second hand. It was primarily used during the approximate period of 1950.