The 4F Regulators incorporate long lasting metal diaphragms (phosphor bronze).  They are recommended for accuracte pressure regulation for steam, air, water, oil and gases.  Generant Regulators are constructed of quality materials throughout, assuring long, trouble free service.  Bodies are forged brass, internal parts are brass or other non-rusting materials.  The self aligning design allows greater air flow with lower pressure drop.  Two port regulators have two in-line ports.  Four port regulators have two additional 1/4" pipe size outlet ports for pressure gauge or other use.