Digitech XBD Bass Driver Bass Overdrive/Distortion Pedal Level -adjusts the overall effect level. Tone - uses special Spectral -Contouring equalization. This adjusts a broader range of frequencies, which provides greater tonal control than is found in typical stompbox tone controls. Blend - adjusts the mix of the dry signal with the effected signal. Morph - selects or morphs through 3 overdrive models, including the TS9 Tube Screamer, the Rat and DigiTechs DigiFuzz. Level -adjusts the overall effect level. Blend - adjusts the mix of the dry signal with the effected signal. Morph - selects or morphs through 3 overdrive models, including the TS9 Tube Screamer(TM), the Rat(TM) and DigiTech's DigiFuzz(TM). Tone - uses special Spectral -Contouring equalization. Morph - selects or morphs through 3 overdrive models, including the TS9 Tube Screamer, the Rat and DigiTechs DigiFuzz. This adjusts a broader range of frequencies, which provides greater tonal control than is found in typical stompbox tone controls.