Pleatco PSS17.5 Replacement Cartridge for Comfort Line Spas; Softsider Spas; ICM, 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 4-3/4-by-1-9/10-inches with handle Made in the USA