The Aqua Flo 41407003 is a 50 gallon per day RO membrane designed for the third stage of the Aqua Flo QCRO 4 stage RO system. The RO membrane is a Thin Film Composite Membrane featuring a quick connect twist and lock design, making service a snap. To keep your system in top shape, change the Aqua Flo 41407003 every 36 months.