The new improved version of the Vyagra boost from Crazy Tube Circuits now comes with a sensitivity knob so you can dial in Auto-wah envelope filter effects. The Vyagra also now includes and expression pedal input so you can use it as a wah pedal. Parametric eq for tone shaping and a killer boost that sweetens and erects your tone! All packed into this tiny pedal! Amazing. The Crazy Tube Circuits Viagra Boost Mk II.