Designed specifically for the Fluval 306/406 and 307/407 performance canister filters, Bio-Foam captures large particles and debris for effective mechanical filtration. Key Features : *Mechanical filter media *Effectively traps majority of waste and debris *Complex foam structure maintains consistent water flow and naturally promotes beneficial bacteria growth *Custom fit to prevent debris bypass *Enhances the biological filtration process *Convenient 2-pack format *Replace every 6 months *For use in freshwater and saltwater aquariums