Universal Design: Tetra Whisper 10i Internal Filter is an all-in-one air pump and water filter system. Internal Filter: Mounts on the inside of your aquarium with clip (included) Catches Debris: Dense, dual-sided mesh filters debris and fish waste. Aerates Water: Air-driven design filters up to 80 GPH while oxygenating water. Convenient Design: Uses medium easy change Bio-Bag cartridges; filter mounts inside the aquarium, making it possible to place the tank flush against the wall. Use in: Aquariums 5-10 gallons in size.