Aqueon Quiet Flow 40 Aquarium Air Pump, Up to 40 Gallons Aqueon QuietFlow air pumps have a wide rubberized base that keeps them virtually silent This size 40 aquarium air pump is 4.6 x 2.8 x 5.9 inches and suitable for fish tanks under 40 gallons Features a vertical design with integrated check valve that positions the air outlet(s) in an upward direction, preventing airline kinking Each air pump has replaceable check valve, diaphragm and filter pad Repair kits are available to replace internal pieces without needing to purchase an entirely new filter