Morley Steve Vai Bad Horsie 2 Wah Pedal w/ Bonus Power Supply Clear-Tone buffer circuit ensures pure guitar tone and maintains signal level in bypass and Wah mode In CONTOUR mode, two knobs allow you to alter the frequency and level of the Wa Switchless design. Simply step on to engage Wah mode and step off to go to bypass TWO foot-selectable Wah modes; Bad Horsie and CONTOUR Wah Works with BASS guitar too!