Electro Harmonix Attack Equalizer original 1978 in Box
The Electro-Harmonix Attack Equalizer is a unique guitar pedal, suitable for use with electronic instruments of all kinds. This is a vintage pedal that is no longer being manufactured. They do have a reissue of the pedal called Knockout, which sounds pretty close to this one. The Attack Equalizer has 1/4" TRS connections for input and output, and has an on/off switch. This isn't a rack mountable piece of gear as it is a stomp box.