Really cool real tube overdrive to push your tone to the next level. Sounds insanely good pushing an already dirty amp (but you knew that already). A must for those Eric Johnson tones. Some of the lower quality capacitors and resistors were swapped out for ones with higher tolerances. Is in fantastic condition and has probably never gigged with. SN: 0809816 Included is the original documentation, pulled parts, and schematics with notes on which parts were swapped. This thing is unbelievable check it out!