Pleatco PFF50P4 Replacement Cartridge for Freeflow Spas Legend, 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 10-by-2-1/8-by-1-1/2-inches MPT Made in the USA