The vuvuzela is a horn, with an inexpensive injection-moulded plastic shell about 65 centimetres (2 ft) long, which produces a loud monotone note, typically around B♭ 3. Some models are made in two parts to facilitate storage, and this design also allows pitch variation. Many types of vuvuzela, made by several manufacturers, may produce various intensity and frequency outputs. The intensity of these outputs depends on the blowing technique and pressure exerted. The indoor noise level caused the U.S. NCAA to permanently ban them after the 7 February 1987 Division I Men's Ice Hockey game between the Brown Bears and the Rensselaer Polytechnic Institute Engineers. The noise was so extreme that Brown formally complained and "The RPI Rule" was universally adopted.

An aerophone is a musical instrument that produces sound primarily by causing a body of air to vibrate, without the use of strings or membranes, and without the vibration of the instrument itself adding considerably to the sound.