Footswitches
Bypass
Turns the effect on and off. LED indicates whether Bypass is on or off
Toggles
G - Gain
Gain boost on preamp side
M - Mid/bass cut
When positioned to the left, a passive tone stack is placed which does limit a little output but gives you a more warm sound with your overall bass tone. When positioned to the right, all restraints are removed giving more output as you will notice a gain increase as well.
F - toggle switch between drive and octave fuzz that is brought into the mix by the blend control.
Knobs
V - Volume
Overall control of volume output
B - Blend
Blend control that blends in drive/octave fuzz (depending on toggle position) as you turn clockwise