Regolatore di tono (m)
(with) definite article: ileach of the hole(s) in the Fonanel(le)
Term for the hole(s) in the Coperchio; Val d’Agri [SE of Potenza]; Also used by Giuseppe Belviso; Scaldaferri dubiously considers them to be ventholes, but they just allow the sound of the keyhole to escape undisturbed, thus maintaining its pitch, and none of them is ever closed/stopped for tuning.
Scaldaferri, Nicola: La zampogna in Basilicata. In: La zampogna: gli aerofoni a sacco in Italia (2005), II, p.59.