Pleatco PWWCT100 Replacement Cartridge for Waterway Clearwater II Above-Ground Pool Cartridge 817-0100N, 1 Cartridge Replacement filter for pool and spa cleaning systems 50% open ABS free flow cores maximize water flow through REEMAY filter media 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 Made in the USA