The Tissot 31-21 watch movement, introduced in 1972, features an indirectly driven minute hand, enabling a large balance and low profile design. It incorporates a barrel with jewel bearings, ensuring smooth and reliable function. This movement can be optionally equipped with raised hands and a spacer, allowing for compatibility with the Forster 422 and casing compatible with ETA 2670. Notable functions of the Tissot 31-21 include automatic winding, sweep seconds, Incabloc Shock Protection, and sweep seconds. The Tissot 31-21 movement has been implemented in watches since 1972.