The Shadow Acoustic and Classical Guitar Pramp with 2 Band EQ is available for passive or active, piezo or foil pickups. Push-Push potentiometers are integrated in an elegant case with integrated battery access. With the EQ-Shape switch you can choose a linear or "V" shaped frequency in the middle position of the tone controls. The phase invert switch is an easy and effective feedback solution. When the potentiometer knob is pushed in, it will pop out and can be adjusted as desired. When done, push it back into the case. Low Battery indicator will turn red when the battery needs to be changed.