This is the best-selling wah in the world and the one made famous by Jimi Hendrix, Eric Clapton, Buddy Guy, David Gilmour, and many other greats. It features heavy die cast construction for years of reliability, 100K ohm Hot Potz potentiometer that allows for that quick, abrupt wah sound. Powered by the Dunlop ECB-003 AC Adapter and/or 9 volt battery which aren't supplied.