Combining four classic germanium transistors, the Germanium Big Muff Pi is the result of a focused modern design dripping with EH analog heritage. Independent overdrive and distortion each have their own set of two germanium transistors as well as independent controls. The ability to stack and use both overdrive and distortion delivers the power of a four-transistor germanium circuit with ultimate control flexibility. Individual overdrive and distortion with the ability to stack together 4 individual germanium transistors Each drive mode mode uses its own 2 germanium stack Overdrive and distortion can be stacked using four germanium transistors Bias and distortion control tone set the tone of the overdrive Volts and Bias set the distortion response Hungry drum sound with voltage control adds character Battery equipped with optional 9.6DC-200 power supply Dimensions in inches: 4 .75 (l) x 5.75 (w) x 2.5 (h) Dimensions in mm: 146 (l) x 121 (w) x 64 (h)