The Parrenin X173 watch movement is a manual wind movement with a sweep second hand. It features shock protection and incorporates a Breguet hairspring. Variants may differ in certain details, such as the length of the regulator hand, the number of crown-wheel screws, the number of balance screws, the presence or absence of recesses for casing screws, and the type of shock device (either Incabloc or Poljot). The movement was primarily used around 1965.