Pleatco PSD40-4 Replacement Cartridge for Sundance 40, 1 Cartridge, 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 16-3/4-by-2-1/16-inches with castle top Made in the USA