The LPB-3 is a linear power booster & EQ, inspired by the "LPB-1" effect pedal that launched Electro-Harmonix in 1968. It features a powerful parametric mid-control and an active EQ capable of boosting up to 33dB, making it suitable for any sound creation. It boosts to the best saturated sound with unprecedented accuracy. (From the manufacturer) Used indoors only for testing. Thank you.