The Fontainemelon 128 watch movement, used from 1958 to 1963, features a flat freesprung hairspring and a DuraBalance regulator. The balance of the movement is equipped with two regulating weights that are simultaneously shifted along spiral-shaped spokes using a regulator lever. Elgin has combined settings for balance, and the shock protection is achieved through elastical balance spokes. Additionally, the movement has manual wind functionality and a sub-second display.
The Fontainemelon 128 features the following functions: