You can flip back and forth between the two gain settings A and B - by clicking switch A or B. The lid (A or B) is indicating the active gain. The pedal is turned off, by clicking the switch (A or B) that is lid.
FEATURES:
GAIN A, GAIN B, LEVEL and TONE
INPUT-Jack 6,3 mm. OUTPUT-Jack 6,3 mm. DC-Jack 2 mm. pin.
9-12V DC or battery 9V Alkaline.
20 milli Amperes