The Gruen 930SS watch movement, which was in use from 1973 to 1976, was the last MST-designed family of movements. All components, except the calendar discs, are interchangeable among the family members. This movement features a hacking mechanism that stops the 4th wheel, with the balance also capable of being halted, although less commonly. The indirectly driven minute hand allows for a large balance and a low profile. Additionally, an optional excenter device can be mounted on the regulator, and the movement includes a rotor with a bayonet joint and a right-handed crown-wheel screw. The 522 movement includes various functions such as automatic winding, sweep seconds, quickset date, hack feature, Incabloc Shock Protection, and stop seconds functionality, making it a versatile option.