The bells are usually cast in bronze and are almost always pear-shaped, or resembling overturned goblets. The outside of the bells is most of the time decorated with geometrical, vegetal and zoomorphic motifs, with religious scenes, portraits of founders, coats of arms and armorial bearing, with votive and liturgical inscriptions, or special inscriptions about the destination of the bells.

According to the Christian tradition, the sounds of bells symbolise the voice of God and of His followers. This is why they are first of all sprinkled with holy water and incensed, sometimes even given a name, a symbolic one or that of its founder, or the name of a saint, with the same ceremonial care as if it were a true baptism.