Electro Harmonix Knockout Attack Equalizer,The Knockout is a powerful two-filter combination that can make your Les Paul sound like a Strat and your Strat sound like a Tele. Its secret…the Knockout has a 7 pole filter for sculpting the low end of your mids and a 6 pole filter to shape the top end of the mids. This provides incredible tone shaping. Use after distortion to bring out the heavy weight punch of the metal masters. The Knockout is also truly amazing on Bass.Power supply not included.