The Auto Shut-Off Permeate Pump Valve will turn off the water feeding the RO system when the tank pressure reaches 90% of the incoming water pressure. This filter is designed to work with permeate pumps, improving RO performance in low water pressure situations (less than 40 psi static water pressure) and increasing the performance of your permeate pump. With an auto shut-off permeate pump valve, you can use more water in the tank without losing pressure. Connects easily with 1/4" quick connect fitting. Using an auto shut-off valve creates extra pressure maintained in the system, increasing pump output.