Airgas Model N140DHF Brass Specialty High Purity High Flow Pressure Regulator With 1/2" FNPT ConnectionThis series of regulators is used for applications requiring high gas flow rates and a compact design. These regulators can handle flows up to 250 liters per minute of nitrogen with only a 5 psig pressure drop. In addition, these units will handle hydrogen flow up to 1,000 liters per minute without the resonance problems associated with other regulators in this same application.