This Replacement filter cartridge has the technical specifications as Unicel # C-4307, Pleatco # PGF7, Filbur # FC3744 and OEM # PGF-7. This 8 inch long and 4 ¾ inch wide filter cartridge has open holes of 1 ¾ inch each both at its top as well as bottom. It is capable of handling the top load of 7 square foot and best fit for General Foam Plastics, Pleatco. It is made of superior grade of materials and gives you complete protection from germs and sand. You get clean and clear water for your spas and it is very easy to install.