Pleatco PLW50-4 Replacement Cartridge for Season Master 50/Molded "O" ring, 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 12-3/4-inches with Male Slip and double handle Made in the USA