The Pentair 4004424 GRO-50EN High Efficiency is an innovative next-generation RO Membrane using "Thin Layer Composite" technology (TLC) to provide enhanced water recovery in an encapsulated membrane. Where traditional RO membranes have a 3:1 ratio of 3 gallons of waste water to every gallon of purified water, the GRO-50EN new technology allows for a 1:1 ratio of 1 gallon of waste water to every gallon of purified water; making it more water and energy efficient. Less waste water down the drain for the same amount of purified water means saving you money and the environment with the same great results! The Pentair 4004424 GRO-50EN model RO membrane includes a drainline flow control, a premeate check valve, a 96% rejection rate, 1/4" quick connect fittings and is 2.5 inches wide by 15.14" inches long with a production rate of 50 gallons per day.