A great distortion for driving tubes and gives solid-state amps a nice warm tube sound. Volume, tone, drive and a switch to change drive type. This is an awesome pedal and can get quite loud. Amazing range of tones roll back on the volume for some sweet chord work. The Tube Drive is based on a JRC4558D chip like in a tube screamer. Has warm and/or smooth crunch. The toggle switch changes clipping type from 2 silicone diodes, to 3 Germaniums, both settings are great. True bypass switching.