The Single stage Regulator reduces the high inlet pressure in one stage to low outlet pressure. Single stage Regulators are recommended where, inlet and outlet pressure variability is acceptable.
    The Double stage Regulator reduces the high Inlet-supply pressure to low outlet or working pressure in two steps resulting in a more constant outlet-delivery pressure. Double stage Regulators are preferred, where there is potential for large inlet pressure variation.
    The Regulators are especially useful for unattended operation, where
the application demands a precise delivery pressure for gas service.