Amazon.com: Vivlex Octave Guitar Effects Pedal Polyphonic Octave Generator Digital Octaver Mini Stompbox with True Bypass Footswitch for Electric Guitar and Bass LEF-3806
EX Analog Octave Guitar Pedal : Amazon.sg: Musical Instruments
Amazon.com: MOOER Tender Octaver Pro, Stereo Octave Pedal with Adjustable between unison and +1/-1 octave Make Your Harmonization, Pitch Shifting, Whammy and Detune Chorus Effects : Musical Instruments