Aqua One Filter Wool Course 200x25cm Aqua One Aquarium Filter Wool is a high quality mechanical and biological filtration media used to remove waste and particulates from the aquarium. Filter wool provides a place for beneficial bacteria to colonise and helps keep water clean. Features & Benefits: Available in three sizes Removes waste and particulates Suitable for a range of filter systems Removes smaller particles than sponge filter media Suitable for: Coldwater, Tropical & Marine We recommend only using Aqua One genuine spare parts in their range of aquariums