The Fontainemelon 221 watch movement, also known as the Wehrmachtswerk or Germany Military Movement, is equipped with a Triostat regulator. This regulator includes three adjustment features: precision adjustment for speed, regulator pin-width adjustment, and a mobile stud carrier. The movement shares similarities with other A. Schild movements such as the 1561, 1587, 1589, 1594, 1606, 1609, 1616, 1617, 1618, 1623, 1648, and 1697. The movement functions as a manual wind mechanism with sub-second functionality.