The AQUATOP AP-50 is a powerful but blissfully quiet air pump for aquariums ranging in size from 20 to 50 gallons. Super low energy consumption saves you money, while several models, like the AP-50, are equipped with a control knob for an adjustable flow rate. AQUATOP's AP Series of electric aquarium air pumps allow your aquatic creatures to acquire the oxygen they need in order to thrive. An air pump system adds air bubbles, creates current and agitates the water to help in filtration. This is where the quiet hum noise of most aquarums comes from. An air pump also aids in maintaining stable and healthy pH levels inside the aquarium.
Features:
Very low energy consumption 
High air flow output 
Super quiet operation 
Max psi at 3.19 
Suitable for aquariums between 20 to 50 gallons 
For both fresh and saltwater use.
Specifications:
Tank Capacity: 20-50 Gallons
Outlets: 1
Air Pressure: 3.19 psi
Adjustable Control Knob: Yes
L/Min: 2.5
Wattage: 3.5
Pressure Max: 3.19psi
Volt/Freq: 110V-120V/60Hz