Blues Overdrive Pedal tonally sits somewhere between a boost / treble booster and a fuzz. The 2 controls are unlabelled, but the left is the output control and the right is the grit control. It also has a bias switch to select between "vintage" or "vintage modern" voicings.
The Blues also contains a trim pot marked "Crystal Lettuce" that controls the voltage going into the pedal. It is set at 7 volts but can be lowered for a spitty fuzz or broken speaker sound, or raised to the full 9 volts for a smoother sound.