Easy installation. There is an option for 4 inserts included, no additional price.
The "input and output" are marked on the top of the valve. Top side of the valve is the high pressure side and the bottom side is the low pressure side.
High pressure from the filter goes to the "in" on the top of the valve. Then the high pressure "out" goes to the membrane inlet. The membrane housing low pressure outlet connects to the "in" on the bottom side of the valve. The "out" on the bottom goes to the tank.