The Tetra® Whisper® Power Filter for aquariums offers quiet 3-stage filtration for clean water and healthy fish. Dual-sided mesh catches debris and fish waste in its dense fibrous network then Ultra-Activated™ carbon provides chemical filtration by absorbing odors and discoloration. Biological filtration is provided by Bio-Foam® which creates a large three-dimensional area for cultivating aerobic bacteria which eliminate toxic ammonia and nitrites. No moving parts means long-term reliability. Uses Stay Clean™ technology to help keep your aquarium clean clear and healthy reduce buildup on aquarium glass and bind small dirt particles to make them easier to filter.