This Replacement filter cartridges replaces Unicel # C-4306, Pleatco # PGF5 and Filbur # FC-3742 while it complies with the OEM # PGF-5 specifications. It is 8 inch long and 4 ¼ wide filter cartridge has open holes of 1 ¾ inch both at the top as well as bottom. It is capable of handling top load of 5 square foot and is best fit for General Foams Plastics, Pleatco. It is the filter cartridge that provides you clean and clear water for your spas and pools free from sand germs. It is very easy to install and is made of high grade of materials.