TC Electronic Classic Series Sustain + Parametric EQ Equalizer Pedal
The Classic Sustainer + Parametric EQ gives you studio quality compression in a guitar pedal. Crank it to the extreme and it'll give your sound that percussive "thud" brilliant for funk or country. And with its parametric EQ you're in full control of which frequencies to target.

One of the true grails of vintage effects pedals. This one really enhances your tone. Go from subtle compression to extreme sustaining effects at the tweak of a knob. This sustainer will prolong life of even your weakest tone otherwise destined for premature death.

Controls
Sustain- Sets the amount of sustain.
Freq Center- Sets the center frequency to be attenuated or boosted by the Function control.
Function- From notch filter type to peak filter type.
Notch settings will attenuate frequencies around the Freq Center. Peak settings will emphasize the selected frequency area. High Q- The "Q" value switch allows you to alternate between two different curve-widths. If you are looking to attenuate an annoying frequency you should most likely use the notch filter type with a narrow Q (out position). If, on the other hand, you are aiming to make general adjustments in a frequency area, the wider Q setting should be used (in position). Experiment.
Output Level - Controls the overall output level of the pedal.
Noise Gate- The Classic Sustain+Parametric EQ comes with a built-in noise gate that can eliminate unwanted noise deriving from pedals placed previous in the signal chain or noise coming from the Classic Sustain+Parametric EQ itself when extreme settings are used.
The single control adjusts the Threshold point. Attack and Release parameters have fixed settings based on common applications.