Zurrón (m)
(with) definite article: elair reservoir: flexible (usually of animal skin), ready for the insertion of stocks
From Euskara [i.e. Basque] "zorro" [bag], or (possibly) Arabic; NB¹: Although Jambrina Leal chooses to write it between quotation marks, it is apparently an alternative term for the prepared bag.
Jambrina Leal reports that a bag with a length of ca. 50 cm allows the piper "to collect air and sing whilst playing"; NB²: A "common" zurrón (for general use) is made of tanned leather.
Jambrina Leal, Alberto: Panorama de la gaita de fole en Zamora, Castilla y Leon [sic]. In: Utriculus IX (34), aprile/giugno 2005, p.10.
ws (linguistics [➺ Dictionaries, &c.]).