It's BYOC's take on the old Ross grey compressor pedal, but they really take it to a whole new level without compromising the original circuit. Controls are Sustain, Attack, Ratio (wet/dry mix), Level & Tone, which are pretty self explanatory. BYOC have put the circuit in parallel with the dry signal so the ratio control goes from 100% dry to 100% wet. The level control (depending on compression setting) can boost the signal above unity quite well & I use this to push the front end of the amp. The tone control makes use of a high pass filter in the original circuit, so isn't an "add on" so much. It can be used to dial in high end jangle, though I dial it back some. The amp I use it with is a tube rectified 50 watt Marshall clone so is capable of compressing enough. As such I have it set to add just a tiny bit of punch, more to fatten the signal & drive the channel jumpered (for Strat) front end of the amp. The result is a more natural or organic tone than the minimally set TS9 gave. The pedal is capable of compressing quite a lot though. Cheers