Features: 1. Provides both mechanical and biological filtration for your tank. The air infusion chamber produces numerous minute bubbles which promotes gas exchange process and increases dissolved oxygen level in water. 2. Easy to set up - Just connect the unit with an air pump thru an airline. It provides both aeration and filtration for your tank. 3. The sponge traps waste particles mechanically and cleans the water without trapping baby fish. It keeps water clean and clear. 4. The aquarium sponge filter are useful for as breeding filter or as secondary filter. Or they can be used as pre-filtration unit by fitting to an external or a top filter. Specifications: 1. Material: plastic & Sponge Caution: 1. Pleasec clean the sponges first before you put them into your aquarium.