White Cap overdrive/boost pedal. This is a tube-driven medium-gain overdrive built in a magnet cover for one of our alnico speakers. Controls for Volume, Tone, Gain. Clear plexi bottom so you can see the inner workings! Uses a 12AU7 tube for gain – but you can use any 12AU7, 12AT7, 12AY7, 12AX7 tube type to experiment with different flavors of gain.