Check the listing for details. MATHESON Model 81L Regulator 3000 PSI (MREG-5181-BA). Condition: New – Open box. Listed at 159.99 USD. IT#MREG-5181-BAReg.Assy,Spec.81L Set at 3.75 PSIG, 1/4 FPT adapt IN/OUT General purpose regulators constructed for use with non-corrosive gases.Applications• Calibration of pressure gauges, rotameters, and mass flow controllers• General purpose applications where a constant delivery pressure is required• Applications with high duty cycle/demanding operating conditions Design Features• Chrome plated brass body• Neoprene diaphragms (1st and 2nd stages)• 2-1/2” inlet and delivery pressure gauges• Equipped with outlet needle valve• 1/4” NPTM outlet connection with loose 1/4" hose barb• Internal interstage relief valve set at 800 psi• One-piece encapsulated seat with (10µ) internal fitter to protect against contamination Materials of Construction• Gauges: Chrome plated brass• Body: Chrome plated forged brass• Bonnets: Chrome plated zinc die cast• Diaphragms – neoprene• Seats: PTFE• Seals: Neoprene Specifications• Maximum Inlet Pressure: 3000 psi (20,700 kPa)• Flow Capacity (Cv): 0.15• Internal Interstage Relief Valve: 800 psi• Operating Temperature: -20°F to 140°F (-29°C to 60°C)• Porting (Regulator Body): 1/4” NPT Female• Porting Configuration: 2 High, 2 Low, 1 Interstage