This high quality replacement filter cartridge can replace Unicel # C-4449, Filbur # FC-2640 and Pleatco # PSI45-O-4 and it meets the OEM # C-4449. This filter cartridge can bear the top load of 45 square feet and is best fit for Conger Bros., Pageant Spa, Santanna. This 17 ¾ inch long and 4 15/16 inch wide filter cartridge has open holes both at its top as well as bottom. By installing this filter cartridge you get clean and clear water for your pools and spas and keeps them free from germs and sand. Very easy to install this filter cartridge is made of superior grade of materials.