Feature: 1. SUPERIOR PERFORMANCE: Aquarium sponge filter catches larger waste particles and mechanically cleans the water without trapping fish. 2. MULTIPURPOSE: Aquarium biochemical sponge filter can be used as a culture filter or as a secondary filter. 3. IDEAL METHOD: Aquarium biochemical sponge filter is a great way to clean fish tanks and cultivate useful bacteria that are beneficial to fish. 4. EASY TO USE: Aquarium biochemical sponge filter is used as a pre filter unit by installing an external or top filter. 5. SAFE MATERIAL: Aquarium bio sponge filters are made of high quality cotton and plastic, are safe, non toxic and odourless and can be used for a long time. Specification: Item Type: Aquarium Bio Sponge Filter Material: Cotton, Pastic. Package List: 1 x Aquarium Bio Sponge Filter