Seriously, 4 control pots are a rather high number for a fuzz pedal to begin with, but I'm still blown away by the huge range of variability each of them brings to the tone. Also some are highly interactive among each other, plus, fuzz is known to really work well with varying guitar knob positions and amp drive. The space of variability resulting from all this really is nothing short of a universe!To be honest it can be quite a challenge to get really great tones out of it, but imo it really is worth the time to dive and try them all. If you think your fuzz face or rat pedals are 1-trick-ponys, this one definitely isn't. If fiddling with controls isn't your thing, then this product clearly is not for you.No idea where to start...there's the BASS control. It brings and excavates truckloads of bass, but if a lot of fuzz and "treble" is present, adding bass also "destabilizes" the tone and cuts some edge from the treble while becomingn less percievable as actual bass.VOLUME does of course add overall loudness, but cranking it also makes the tone more mid-forward and a bit more crackling.The TREBLE control is the weirdest of them all. It is definitely not just cutting or adding treble - it rather sets bias for a transistor or something. That does add quite an amount of treble in the upper section of its range, but the lowest treble setting isn't full left, but somewhere in the middle. Going down from there adds some treble again, but in a very different way and clearly less than the higher half. Adding treble in either way also feels like adding some fuzz/distortion. "Left" and "right" treble also react differently to BASS and FUZZ controls.Speaking of FUZZ, the big knob definitely does what it's calle like, especially in the lower half of its range. Going way up also adds a lot of top end hiss, frequency-wise even above the treble control region. Adding both, FUZZ and TREBLE really is harsh to the ears -co e by either turning either down or adding more BASS or even VOLUME (to make it more mid-forward, remember?) You see, possibilities are endless. Having and pushing a driven amp (crunch to lead channels) and cranking co tools can give yo something even resembling HM2/chainsaw tones, while there definitely are different yet oh so sweet spots for blues solos, downtempo rhythms and grunge "distortion". Haven't had the opportunity to play a single coil guitar, but I have a strong feeling I'm missing out on something there. Can't wait for such an opportunity to finally happen!Didn't mention the huild quality yet - for a Chinese build it feels really sturdy - massive metal case with reasonably sized screws. Also very easy disassembly. If that's the future of Chinese engineering, then brace for impact, west! Let's dive into circuit speculations another day - I leave you photo's for your own puzzling fun. To resume: just buy it, there's little to regret.