Specifically designed for Fluval Spec & Flex Aquariums, Fluval Foam Filter Block provides critical stage 1 mechanical filtration by trapping large particles and debris.It comes with a convenient handle for easy, no-mess handling. Key Features: Specifically designed for Fluval Spec/Flex Aquariums Provides critical stage 1 mechanical filtration Traps large particles and debris Comes with convenient handle for easy, no-mess handling