Why Use Generic Cartridges? The best answer is that they are less expensive. Filbur manufactures the same cartridges as the original Hayward, Pentair, Sta-Rite, and Jacuzzi Pool Filter Cartridges using genuine Reemay spunbound polyester media. It's the same cartridge just less money. The End Caps for the Pool and Spa Filter Cartridges are made from a durable polyurethane material. The center cores of the cartridges are comprised of punched PVC pipe for consistent flow.