Pleatco PH105-4 Replacement Cartridge for Harmsco Tropic Flo 100, BF100SC, 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 19-1/2-by-2-5/8-byb-3-1/2-inches FPT Made in the USA