A spring mechanism refers to a type of game piece, so-called "devices", used to move a game piece. Its function is based on a metal spring. The player uses a finger to pull back the movable part of the figure, most often a plunger or a striker, which compresses the spring. Upon release, the spring returns to its original position and transfers energy through the striker to the game piece, which then moves. The force of the strike is regulated by the extent to which the mechanism is pulled back.