Filbur FC-3753 Antimicrobial Replacement Filter Cartridge for Aqua Leisure/Intex Pool and Spa Filter, Set of 2 High performance pleated polyester media. Reinforced antimicrobial end caps Extruded pvc center cores. Molded in threads, no loose inserts Measures 4-1/4-inch diameter by 3-3/4-inch length. 2-1/16-Inch top hole, 2-1/16-inch bottom hole. Top 2-1/16-inch open style, 2-1/16-inch open bottom style. 2-1/2-Square feet area and weighs 3-ounce. Replaces Unicel and Pleatco filter cartridge models C-4313, PBW4PAIR. Set of 2.