Pleatco PWW10 Replacement Cartridge for Waterway Skim Filter 10, 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 4-by-2-1/16-by-2-1/16-inches Made in the USA