TTONE Guitar Effect Pedals Clean Booster Boost Metal Guitar Effects Pedal True Bypass Kit (purple) Full metal shell, exquisite and big sound. Use the highest quality parts and low impedance output. Single knob control to adjust the degree of booster. XP booster provides up to +20dB of unadulterated boost with multi-dimensional shimmering that highs and lows, and no ear fatigue. NOTE: In order to let buyers experience the fun of assembling, It need you to assemble it by yourselves.If you'e not 100% sure you could make it assembled successfully, please purchase prototypes directly.