Gain : Placed after the Jfet transistor input stage and followed by silicon gain and clipping stages. 

Master : Master volume. 

Blast : Controls the amount of the feedbacked fuzz when you engage Crash footswitch.

Low Pass Filter CutOff : This fader controls the cutoff frequency of the MS-20 style low pass filter. Based on a LM13700 stage. Goes from 15Hz to 38kHz. 

LPF Resonance : Increases the intensity of the signal around the cutoff frequency.

2p/4p toggle switches : Select the attenuation curve. Cut at -12dB/octave (2p) or at -24dB/octave (4p). 

High Pass Filter CutOff : This fader controls the cutoff frequency of the MS-20 style high pass filter. Based on a LM13700 stage. Goes from 15Hz to 10kHz. 

HPF Resonance : Increases the intensity of the signal around the cutoff frequency.

Filter Volume : VCA - sets the output volume of the filter. Pretty useful to adjust the filter to your setup.

Add Fuzz (long press Crash footswitch) :  Adds an extra unfiltered fuzz signal. The result is louder and creates a nice phasing effect and cool frequencies boost or cut depending on the cutoff position.

Serial - // toggle switch : Put the fuzz into the filter - or use both effects in //. 

LPF/HPF Expression toggle switch: Select on which filter the expression pedal acts. 

Expression/CV : The Expression/CV control is linked to the cutoff fader of your choice. The cutoff fader value sets the lowest value the EXP pedal can go.