Finest-Filters 5 x Compatible Biorb Filter Set / Service Kit 5 x Replacement Compatible Biorb Filter Service Kit Simply remove old media from your filter, retaining the plastic housing, and insert our media replacements, followed by the foam ring. This kit contains 5 x foam rings, and 5 x sachets of Carbon/Zeolite Mix. Note: This is not a genuine Biorb product. This is a Finest-Filters alternative, which serves the same purpose.