Pleatco PRB35-IN Replacement Cartridge for Dynamic Series IV - DFM, DFML, Waterway 35, In-Line, 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 9-1/4-by-2-1/8-by-2-1/8-inches Made in the USA