Pleatco PLBS100-M Replacement Cartridge for Leisure Bay, S2/G2 Spa 100-Square-Foot (MICROBAN), 1 Cartridge Replacement cartridge for leisure bay, s2/g2 spa models 50 Percent 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 Replaces unicel C-5397 and filbur FC-2972; made in usa; microban inhibits the growth of stain and odor causing microbes like bacteria and algea Measures 5-5/16-inches in diameter by 17-3/4-inches in length and 2-1/8-inches of top and bottom hole diameters