Without switch, triggering when the foot is placed optical Morley circuit eliminating potentiometer noise 2 modes: Wah, WHOA (exaggerated with more harmonics) -Wah Lock function with notch potentiometer for frequency adjustment, operating in both Wah and WHOA modes +20 dB boost with adjustment potentiometer classic sound with MQ2 inductor buffer on 9V battery or DC 9V adapter LED running indicator metal case Dimensions (mm): 174 (L) x 114 (d) x 63.5 (h)