This Replacement filter cartridge replaces Unicel # C-4602 and Filbur # FC-3811 while complies with the OEM # C-4602 specifications. With its 8 inch length and 4 5/16 inch width this filter cartridge is can handle the top load of 8 square foot and it is best fit for Muskin, Sears. This high quality filter cartridge has 2 3/16 inch open hole both at the top as well as bottom. Very easy to install this filter cartridge is made of superior grade of materials. By installing this filter cartridge you get complete protection from germs and sands in your pools and spas.