This filter system has set the standard for quality, superior flow rates, and unmatched water clarity. This filter system has a built in pressure gauge and air relief valve. The rugged filter tank is constructed of tough weather resistant and corrosion proof polymer plastic. Inside, our extra large filter elements produce water quality superior to sand filters without backwashing. Large 1inch drain plug to ensure easy clean up and quick water drainage. They require a minimum of cleaning, insuring hassle free operation.