Andoer XP Booster Electric Guitar Effect Pedal Mini Single Effect with Clean Boost True Bypass Full metal shell, exquisite and big sound. Single knob control to adjust the degree of booster. Use the highest quality parts available with a discrete FET design and low impedance output. XP booster provides up to +20dB of unadulterated boost with multi-dimensional shimmering that highs and lows, and no ear fatigue. The internal DIP switches let you choose the boost frequencies, and EQ settings. The light flashing when working. True bypass in order to protect signal integrity when the pedal is not engaged. Foot-switch toggle controlling on/off condition.