The FDXi offers a balanced diaphragm. The balanced diaphragm is inherently environmentally sealed. Water enters the main spring cavity and the pressure increase from the water is transmitted to the internal components by the impermeable diaphragm membrane. The benefit of this type of first stage design is that none of the delicate internal parts are exposed-to-contaminants such as salt, sand, chlorine or pool acids. These environmental contaminants can cause corrosion and mineral deposits to form on the internal mechanism deteriorating regulator performance. A diaphragm first stage regulator requires less-maintenance then regulators that allow these contaminates to enter the internal mechanism.