The Fireburst is that thick low-end heavy saturated fuzz you have been looking for. The mid-boost switch adds loads of tonal versatility and a pre/post gain circuit snaps the fuzz into a more focused distortion pedal. The EQ section is an active Baxandall bass and treble control that act independently at extended frequency extremes - <150 Hz and > 3 kHz, which gives you some interesting post-distortion tonal shaping.