Mad Professor SKY BLUE Overdrive Guitar Effects Pedal - Hand WiredMad Professor Sky Blue Overdrive (SBOD) is a very unique four knob pedal designed to overdrive already distorted amplifiers as well as provide light overdrive or soft distortion on clean sounds. Special feature on this pedal is that you can adjust the feel and dynamics with Texture and Z knobs. The Texture allows changing how and when circuit distorts as well as adjusting overall EQ. The Z is a control that creates an adjustable load to the instrument