The Fluval Bio-Max Rings are a product designed to enhance the filtration system in fish tanks and aquariums. Made by the brand Fluval, these rings provide a surface area for beneficial bacteria to colonize, aiding in the biological filtration process. With a weight of 500g, they are compact and easy to install, making them a convenient addition to any aquarium setup. Fluval Bio-Max Rings help maintain water quality and promote a healthy environment for fish and other aquatic animals. Brand new in sealed box.