The Fuzz Face is an effects pedal used mainly by electric guitarists, and by some bass players. It is a stompbox designed to produce a distorted sound from an electric guitar

Electric guitar

An electric guitar is a guitar that uses the principle of direct electromagnetic induction to convert vibrations of its metal strings into electric audio signals. The signal generated by an electric guitar is too weak to drive a loudspeaker, so it is amplified before sending it to a loudspeaker...

. This "fuzz" sound is sometimes compared to the sound of a damaged speaker. In fact, early efforts to achieve this type of sound included actually ripping or poking holes in guitar amplifier speakers.
Arbiter Electronics Ltd.