The Seiko 7625D watch movement, introduced between 1951 and 1957, is the first rotor automatic from Mido. It employs a lever, ratchet wheel, and pawl wheels made of beryllium bronze. The movement features a detached manual wind mechanism and incorporates the Incastar regulator, a unique and widely produced regulator that includes a free oscillating hairspring. The hairspring is fixed between two rollers, allowing for length adjustments without introducing isochronism errors from the gap between the regulator pins. The Seiko 7625D movement also includes functions such as automatic winding and a sweep seconds hand.