Krpa (f)
Plug, used to stop the upper end of the cane reed base, if not closed by a natural node; Žegar.
Made of a small piece of cloth, steeped with beeswax, plugged into the upper opening of the reed base and smoothened with beeswax on top.
Širola, Božidar: Sviraljke s udarnim jezičkom [Aerophones with a beating tongue]. Zagreb, 1937, p.211.