Key Features Genuine Oase Media Biological Ceramic Rings For the FiltoSmart Aquarium filters Suitable for other Aquarium Filters that require Ceramic media Helps to keep water clean and healthy Oase Genuine Ceramic Filter Media. These white ceramic rings fit into the FiltoSmart Aquarium Filter by Oase. The rings are effective biological media that good bacteria thrive on inside your aquarium. This good bacteria helps to break down sludge and algae to make it easier for the filter to handle and clean. The result is clean and clear water. It is recommended to replace media every 6 -12 months