The Filtrex CYST Series GreenBlock Filter, FX20CYST is a fantastic device that comes with a great capacity to hold impurities. It is a great option for removing chlorine content, bad taste and foul smell from water and making it safe for drinking. It has been certified by NSF for delivering high standards of material safety. With a capacity to hold 45,000 gallons of water, this device delivers a flow rate of 2 gpm. The technology used in its design helps in reducing the harmful Green House Gas Emissions too.