Zills, also zils or finger cymbals (from Turkish 'zil', "cymbals"), are small metallic cymbals used in belly dancing and similar performances. They are called 'sājāt' in Arabic. They are similar to Tibetan 'tingsha bells'. In western music, several pairs of zills can be set in a frame to make a tambourine.

A set of zills consists of four cymbals, two for each hand. Zills come in a range of sizes, the most common having a diameter of about 5 cm (2 in). Different sizes and shapes of zills will produce sounds that differ in volume, tone and resonance. American Tribal dancers typically use a much larger zill with a more mellow tone.

Zills played as idiophones, two on each hand, can be played in many ways to produce a wide and subtle range of sound, from quiet clicking, bell-like ringing, muted cupped sounds, loud clacks, and even a small range of pitch change.

Zills belong to the family of instruments used in Ottoman military bands and also occasionally appear as part of Western orchestral or other musical performances. In these cases musicians usually just call them finger cymbals and use them to obtain a ringing sound with "Middle Eastern" associations.

Percussionists who are not exclusively cymbalists sometimes play finger cymbals by striking one cymbal with a drumstick, or by holding one cymbal in each hand by gripping the strap between the thumb and the index finger, and striking the rims together.

More Info: en.wikipedia.org