BOSS Oc-5 Octave Guitar And Bass Effect Pedal with Vintage And Poly Modes Plus 5-Year Warranty : Musical Instruments - Amazon.com
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