The new shape of silence. The Whisper Air patented dome shape and sound dampening chambers minimize turbulence and produce a smooth quiet stream of air. Wide footprint; rubber feet and suspended pump motor eliminate sound producing vibrations. Thick walls insulate motor noise. Powerful diaphragms provide ample airflow for deep water applications. The versatile pump can be used for several applications including powering undergravel and sponge filters; airstones; and air-driven ornaments. The Whisper 40 model has one outlet and is rated for aquariums up to 40 gallons. Using an air pump adds dissolved oxygen to your water; improving the overall health of your aquarium. For more information on aquarium aeration; please see our article on Air Pumps.