Pleatco PSG25P4 Replacement Cartridge for Saratoga Spas After Hours Spa, 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 6-1/2-by-1-1/2-inches MPT with handle Made in the USA