Maintains optimum air flow, even in the deepest aquariums. Can be used even in sound-sensitive environments. Do not place in aquarium water. Do not install or store where it will be exposed to weather or freezing temperatures. For indoor use only. Features A Replaceable Diaphram And Valve Block. Rate Can Be Easily Adjusted. Rubber, Plastic, Glass, And Metal. Unit Contains Two Adjustable Air Outlets. For Indoor Use Only. Contains One Air Pump And Instructions For Installation. 30 GALLON