Penn-Plax presents the Cascade 80 Hang-On Filter Replacement Media Cartridges. This 1-Pack of Cascade Poly Fiber Floss and Activated Carbon Media Cartridge is specially designed for Cascade 80 Power Hang-On Filters, allowing for simple and easy media replenishment. Safe for freshwater and saltwater aquariums. Double-Sided: The media cartridge contains finely constructed Poly Fiber Floss at the front, and 1 ounce of research-grade Activated Carbon at the back. Furthermore, the internal rib structure evenly distributes Carbon throughout the cartridge for the most effective filtration. Clean & Healthy: This piece traps floating particulate matter, removes harmful chemicals and toxins, clears up discolorations, and reduces foul odors from your aquarium's water. The media cartridge helps keep water inside your tank crystal clean. Measurements: 5.25” x 2.75” x 0.75”. Shop Penn-Plax for All Your Pet's Needs: Penn-Plax is a manufacturer and distributor of top quality pet supplies, who specialize in creating excellent pet products for animals, both great and small.