The Electro-Harmonix Knockout Pedal can give your tone the heavyweight punch it deserves. Two powerful filters are the key -- make your humbuckers sound like single coil pickups and your Strat sound like a Tele. Amazing on bass! The Knockout Attack Equallizer lets you tweak the high-pass and low-pass filters, changing your sound from Gibson to Strat to Telecaster, with innumerable shades in between.Controls: Low, Dry, High. 1/4" input and output DC power input for battery replacement. LED indicates whether effect is engaged or bypassed.