Klinger Fuzz Drive unit is 2 independent pedals in one. A medium drive and very transparent overdrive section with controls for bass, high roll off and internal trim to shape mids - plus a very tweak friendly fuzz section with internal control over presence, bias, input saturation and the normal Fuzz, Volume knobs. The fat switch on the front is for thin sounding pickups that need a tiny beef up or cut it for dark neck pickups and humbuckers that are muddy with fuzz. The Fuzz is set around NOS Tin can silicon transistors used in the vintage fuzzes of the late '60s early '70s. The idea of this pedal is to be the perfect balance between clean amp, overdrive and fuzz.