The Aquascape Pond Filter Urn Filtration Replacement Kit provides replacement biological and mechanical filer media for the large-sized Aquascape Pond Filter Urn (model 77011). The included ceramic filtration rings and media net, providing substantial surface area for beneficial bacteria to colonize. The replacement filtration kit also includes a filter mat, providing efficient mechanical filtration, reducing maintenance and helping to provide clear water conditions. Biological media net included. Aquascape is passionate about the products we produce, providing unique products, designs and features that stand above the competition.