This is what Electro-Harmonix says about this pedal.

Re-create the sounds of a classic fuzztone pedal with the EHX Satisfaction Fuzz, now updated with true bypass circuitry for optimum signal path integrity. The Satisfaction fuzz features an elemental two-knob layout with controls for Volume and Attack (fuzz). True to the genre, this classically-voiced fuzztone creates a sound that is anything but subtle and goes from an aggressive rasp to full-on fuzzed-out mayhem!