Replacement Pool & Spa Filter: C-8399 (73722, 77812, FC-3965, PCD100W, 81004) filter cartridge features 100 square feet of 3-ounce basis weight media that catches debris and particles, keeping your hot tub water clear.  Compatible with Catabria 2014 Q3 to present. 2005 to present Aspire, Tahitian, Niagra, Geneeva & Elation spas.