The Wah was based on a 1967 Class A circuit design that featured the unique Halo inductor. BBE has re-engineered and custom-tuned the Halo inductor and potentiometer to re-create the expressive tones made famous by players like Eric Clapton, Jimi Hendrix and Stevie Ray Vaughn. In addition the Wah has a “Harmony” control to help fine tune the Wah’s Q/peak response and hand-wired all components for the ultimate in vintage authenticity.