Before the introduction of the euro, francs were also used in France, Belgium and Luxembourg, while Andorra and Monaco accepted the French franc as legal tender (Monegasque franc).
Inside the caliper is a brake pad, a small block of friction material backed with a metal plate. When you step on your brake pedal, pistons inside the caliper cause it to apply pressure to the brake pad which squeezes the rotor, causing the car to slow or stop.
The car manufacturer will specific a minimum thickness for the face of a rotor, and they will need to be replaced when this is not met due to wear. Caliper: The calipers are the pieces that squeeze the brake pad onto the rotor, applying a large force which will stop the wheelâs rotation.