Pleatco PWWEK150-M4 Replacement Cartridge for Waterway Eco-Kleer 150, 1 Cartridge Replacement filter cartridge for pool and spa cleaning systems 50 Percent 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 Replaces unicel and filbur; made in usa; microban inhibits the growth of stain and odor causing microbes like bacteria and algea Measures 10-inches in diameter by 23-1/8-inches in length and 6-inches of top and bottom hole diameters