Shimmer reverb traces back to Brian Eno's early-1980s experiments and became widely known through U2's The Unforgettable Fire. Here the octave sits inside the reverb decay rather than on the dry signal. The pitch layer therefore only appears as the reverb is turned up, and the pedal cannot act as a dry octave effect.

Verb sets the amount of reverb, Octave blends the pitch-shifted layer into it, and Decay sets the tail length. The Up/Down toggle chooses the octave above, for bright pads, or the octave below, for a darker bed under chords. With Octave turned fully down, the pedal works as a plain reverb. The effect also sits well after drive pedals for ambient lead lines.

The same line also includes the 3 Series Reverb and 3 Series Hall Reverb for players who want reverb without the octave layer.