Pleatco PSTG5 Replacement Cartridge for Comfort Line Spas; Spas To Go, 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 8-by-2-by-2-inches Made in the USA