Utri (m)
(with) definite article: ? [il [lu?] ?]: l’air reservoir: flexible (usually of animal skin), ready for the insertion of stocks
From Latin "ǔter" [goatskin / leather bag; wineskin].
Made of the skin, with the hair on the inside, of a not too old "sterile" goat, and therefore with very small teats.
Bonanzinga, Sergio: La zampogna a chiave in Sicilia. In: La zampogna: gli aerofoni a sacco in Italia (2005), II, p.193.