This unique and famous effect was popularized by Peter Frampton, Joe Walsh, Aerosmith, Bon Jovi, and others. The sturdy metal casing houses a phenolic diaphragm speaker, powered by your amplifier's external speaker jack. (Place it in line with your external speaker, which can remain connected.) A 6-1/2 foot surgical tube carries the diaphragm speaker's sound to your mouth. The tube end is placed near a vocal mic. By shaping sounds with your mouth, you immediately achieve the "talking" guitar sounds that you've heard on so many hits. Power: Powered by your amplifier's external speaker jack.