1.High-quality sponge filter can provide both mechanical and bio filtration. 2.High-quality sponge filter has air infusion chamber produces minute bubbles which increase the oxygen solubility. 3.Easy to clean: simply take out the 2-bio sponge, wash it in tank water every month then can reuse. 4.This high-quality sponge filter color is easy to hide the algae, and more match to your tank landscape. 5.Culture beneficial bacteria, increase the water level. Don’t wash the sponge in tap water or hot water, or it will reduce the QTY of beneficial bacteria only wash in tank water. 6.The high-quality sponge filter is safe for fish, soft sponge material, tinny holes, won't suck up your fish.