For idiots like me; this is a Korg pedal and seems to be for Korg only, no polarity switch :p On my Yamaha synth, it seems I only get the "press to dectivate" sustain function, since there's no polarity switch. It says so clearly in the description, but I was dumb enough to miss that :p So to all other stupids out there, it has NO POLARITY SWITCH!! :p