Replacement cartridge for Pentair pool prods, pac fab mytilus FMY 100 * 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-7699 and filbur FC-1950; made in usa; microban inhibits the growth of stain and odor causing microbes like bacteria and algea * Measures 7-7/8-inches in diameter by 22-1/8-inches in length and 3-1/16-inches of top and bottom hole diameters