Set of four Filbur FC-1976 Replacement Cartridge for Pentair Clean and Clear Plus 320, Pack of 4 Cartridges (FC-6465) Convenient quad pack cartridge Reinforced antimicrobial end caps Extruded pvc center cores Break resistant bands,Molded in threads, no loose inserts Replaces Pleatco PCC80,Replaces Unicel C-7470,Replaces Filbur FC-1976 and Compatible with Pentair Clean and Clear Plus 320