Zils, or zills, are finger cymbals used by modern ethnic dancers, notably Middle Eastern dancers.  Your Author has not found any period examples of their use, in armory or by dancers.

When borne in pairs, by Society convention, zils are arranged as worn on the dancer’s fingers:  in pale, the lower one inverted.  For related charges, see bell, musical instrument.

Stevanna of Houghton bears:  Vert, an arm embowed with hand to sinister argent, holding zils, with four armbands and entwined by a double-headed serpent, all Or.

Baraka bint Hasan al-Fahim bears:  Azure, a pair of zils between two scimitars addorsed crossed at the hilts argent.

Bahita of Abu Simbel bears:  Azure, a bend sinister Or between a zil bendwise and another bendwise inverted, all within a bordure argent.