Green Ringer - Octave Up Guitar Effect DIY Pedal Kit | eBay
TC Electronic SUB 'N' UP OCTAVER Next-Generation Polyphonic Octave Pedal with Monophonic Octaver and Built-In TonePrint Technology, Compatible with PC and Mac : Amazon.co.uk: Musical Instruments & DJ
17 Best Octave Pedals in 2023 (All Price Ranges) | Guitar Lobby
Electro-Harmonix POG Polyphonic Octave Generator | Reverb Australia