Zills or finger cymbals
Finger cymbals, also known by their Turkish name, zills, are used to create musical accompaniment for belly dancing. The Tribal Bellydance website recommends that prospective zill buyers should choose good quality instruments at least 2" wide with sturdy 1/4" elastic.
These little instruments are made of metal. Plenty of cheap ones are available, but a dancer is well-advised to choose good quality zills that have an appealing sound.