Feature:1. The sponge can effectively prevent the inhalation of shrimp and small fish, and prolong the use of filter materials.2. Prevent weed from entering the filter tank to reduce the filtering frequency.3. Can clean the water inlet pipe, reduce sewage deposition, and reduce the attenuation of the filter element flow.4. The material has great thickness, it is durable and very suitable for using in freshwater and marine water.5. Lightweight, softness design and excellent water permeability,dense shape makes it effective to avoid residue.Specification:Conditon: 100% Brand NewItem Type: Biochemical Filter SpongeMaterial: CottonColor: BlackOuter Diameter: Approx. 4.9cm/1.9inHole Diameter: Approx. 2cm/0.8inLength: Approx. 9cm/3.5inUsage: Fit for aquarium filter.Package List:10 x Biochemical Filter Sponge