GFI SYSTEM ROSSIE FILTER Dynamic Multi-Filter Pedal Brand: EFFECTOR GFI System ROSSIE Reportedly used by Cory Wong. This is an envelope filter effector. I put it on my board after purchase, but I'm selling it because I haven't used it much. It works perfectly with no issues. Please refer to the photos for the condition. Only Velcro for use on an effector board is attached to the back. I believe it's in beautiful condition with no scratches based on my amateur assessment, but please refrain from purchasing if you are sensitive to such things. #EnvelopeFilter #Filter #Effector #Guitar #CoryWong #CoryWong