Pleatco PSANT20-X4  Replacement Cartridge for Futura Spa (Strong Industries) Antigua, 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 7-1/16-by-1.9-inches Keyed with handle Made in the USA