Also known as the Jews' Harp, the Jaws Harp is a hand-sized instrument placed in front of the mouth. Its name is misleading, as the Jews' Harp is neither a harp nor associated with Jewish tradition. It has a long history, and has remained popular because it is portable and relatively easy to play.
The Jaws Harp is usually made of forged metal (usually iron, sometimes silver), with a metal reed within a thin metal frame. The closed end of the frame is a single key or tongue which you pluck with your finger to create various buzzing tones by holding the closed end in your mouth and changing the size and shape of your mouth.