This Replacement filter cartridge is made of high quality material and can be installed very easily. It replaces Unicel # C-4327 and Filbur # FC-0640 while complies with the OEM # C-4327 specifications. This 11 7/8 inch long and 4 5/8 inch wide filter cartridge has open holes of 2 1/16 inch each both at its top as well as bottom. It is able to handle the top load of 25 square foot and best fit for American Commander 11. By installing this filter cartridge you get complete protection from germs and sand.