The Spring Reverb pedal is a simple but very powerful effect. With three very useful controls, this is a really easy reverb to dial in to those fantastic spring reverb sounds, Dwell will determine how long much of the spring lasts after playing a note and the Tone will take it from dark sounding to a bright twangy sounding reverb. And finally, you've got the Mix to control the overall volume of Reverb added to dry guitar signal.