EZ-FLO Ball Valve Coupling connectors are socket x socket connections. They are PVC schedule 40 on both ends. Each end also has a 1/4 nylon barbed tubing connector protruding from the top. They are used to connect the EZ-FLO system to the irrigation flow line with the 1/4 flexible tubing provided with the EZ-FLO system when the elevation of zone valves downstream from the EZ-FLO System installation point are at an elevation 10 feet or more above the installation point. They provide the ability to adjust the differential pressure between the inlet and outlet connection to the irrigation system flow line and can ensure that even the heaviest organic fertilizers and supplements can be pulled from the tank.