it is an extremely simple booster, copied a bit on the MXR microamp. The pedal is old, so no external power supply, a single gain setting.
the knob will zero sound (unlike that microamp from a neutral volume) to a true big bad boost that scares lamps.
it's pretty radical and it will actually serve kick for a lead or a biting rhythm. the boost is not neutral and emphasizes good highs and mids that make aggressive and nervous about his wish. staining is useful because if you are slight crunch, the boost will help to crack more clearly lamps amp for a rare outcome.
It is more violent than the MXR and will not be made to equalize the levels of two guitars.
no loss of treble bypass despite the ancient technology, it just takes the right dose point boost depending on your config. The effect still time is not neutral but transparent frequencies for guitar. A good alternative to an OD / booster that compress too much.
Very interesting because it seems that it's the same buffer bypassed.
Overall, this is a pretty cool curiosity, which gives a lot of pep, blues or pop a little dirty.