LOKNOB PRO LARGE PEDAL ACCESSORY - BLACK. LARGE METAL lock for potentiometer in BLACK finish. Store and lock the settings on your pedals, instruments, amps and studio gear with the Loknob! Simple, without tools or manuals. Just replace the original knob on your device's potentiometer with the Loknob and pull it to adjust it to the point you prefer. Release it later and the button will stay in place until you pull it again. As simple as that!