EZ-Flo HI-FLO Coupling Connection with Ball ValveHi Flo Coupling (HFC) ball valve connectors are available for mainline sizes ranging from 2 to 4 with socket x socket connections for gluing into PVC pipe. They are manufactured from Schedule 40 PVC with adaptable tubing connections, having 3 8 and 1 2 connections standard. The HFC is primarily used to connect the Engineered Systems but may be adapted to other models as well when necessary. The HFC provides the ability to adjust the differential