4 Pack Pleatco PA90 90sqft Filter Cartridge for Hayward C900 CX900RE Sta-Rite PXC-95 Replacement filter for pool and spa cleaning systems 50% open ABS free flow cores maximize water flow Antimicrobial end caps resist chlorine degradation and provide support to filter material for a longer life span 17-3/8-by-4-by-4-inches 4 Pack