For the ultimate in convenience and quiet, choose a Whisper-« In-Tank Filter. These filters mount on the inside of the aquarium, rather than hanging from the outside -- making it possible to place the tank flush against a wall. In-Tank Filters are unusually quiet, since the motor is under the water. Offering the same quality and performance as an external filter, the Whisper-« In-Tank Filter will function in as little as 2 inches of water -- making it ideal for turtle tanks, or for creating a waterfall inside the tank. The Whisper-« In-Tank filter features adjusts easily to high or low water levels with mounting suction cups and/or bracket. Each filter comes with one pre-assembled Whisper-« Bio-Bag-« filter cartridge.