I could theorize with this all day! SubDecay Octave Theory Octave Modulator/Synthesizer, $159!

Effect Type: Octave pedal

Brand: Subdecay

Model: Octave Theory

Type: Analog octave pedal

Controls: Blend, Range, Tone, Up Octave, Down Octave

Inputs: 1 x 1/4″ (instrument)

Outputs: 1 x 1/4″

Power: 9V DC power supply (sold separately)

Dimensions: Not provided (varies depending on version)

Weight: Not provided (varies depending on version)

Additional Features: True bypass, sturdy construction, LED indicator, octave-up and octave-down control, versatile octave sound shaping capabilities