Help keep your tank sparkling clear and simplify your filter maintenance with Fluval Pre-Filter Media. Made specifically for multi-stage canister aquarium filters, it provides medium and coarse filtration that captures solid waste and other large debris before they reach the other filter stages. Pre-filter media boosts water clarity and prevents premature clogging of finer filters, which extends their life and reduces the frequency with which other filter media needs to be replaced. Made of chemically-inert ceramic material, this product is designed for use in Fluval canister filters and is suitable for both fresh and saltwater environments.