The Tissot 28.5-1 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 Tissot 28.5-1 movement also includes functions such as automatic winding and a sweep seconds hand.