http://www.proanalogdevices.com The Lady Evil from ProAnalog Devices is a 4 silicon Fuzz that takes you from warm, classic fuzz tones through to gated circuit-bent fuzz. I love this pedal. It's bold and raw but has sustain and feels great to play. Swell is volume. Filter is an EQ that changes the texture as well. With it counterclockwise and the Attack cranked, you get gated. Clockwise is warm and vintage. Sustain gives you starved to full and clear. Attack is the amount of fuzz. A very versatile and rich sounding pedal.