The regulating member of a timepiece generally includes an inertia wheel, called a balance, and a resonator called a balance spring. These parts have a determining role as regards the working quality of the timepiece. Indeed, they regulate the movement, i.e. they control the frequency of the movement.
In the case of a double balance spring, materials have been tested in order to limit the influence of a temperature change on the regulating member in which it is integrated, without resolving difficulties regarding assembly or resonance adjustment.