Sorry no idea. I took a piece from the car and found the black charcoal loaded aquarium filter seemed an almost perfect match so only tried that. In my aquarium the filter set had black charcoal filters, Blue course and green fine filter elements. From the aquarium manufacturers they were quite expensive but the shop owner showed me the rolls of filter medium at a fraction on the price. It was years later I bought a Morgan and when I found the heater filter breaking up remembered the aquarium medium.
BR
Colin
