The Certina 17-12 is a manual wind mechanical watch movement that features a sweep second hand. It incorporates a Breguet hairspring and combines settings for the escape wheel. Some later samples of the movement are equipped with a ring balance. Different variations of the movement exist, which may include differences in the regulator hand length, number of crown-wheel screws, number of balance screws, presence of recesses for casing screws, and the use of either Incabloc or Poljot shock devices. The Certina 17-12 movement was commonly used in watches produced around 1965.