The instrument is an idiophone consisting of a flexible metal tongue attached to a frame. This tongue is placed in the performers mouth and plucked with the finger to produce a note. The note thus produced is constant in pitch, though by changing the shape of their mouth and the amount of air contained in it the performer can cause different overtones to sound.
The name Jew's harp, may derive from its popularity amongst Eurasian steppe-peoples like the Khazars perhaps being introduced to Europe from that direction.