Airgas Model N245D350 Brass High Purity Two Stage Pressure Regulator With 1/4" FNPT Connection And Non-Lubricated Check ValveThis series of two stage, high purity regulators is designed for non corrosive analytical and process applications requiring precise, stable, delivery pressure control. The two stage design yields a delivery pressure of less than 0. 02 100 psi inlet change. These regulators come with a CGA nipple that has a special high purity, non lubricated check valve incorporated into nose and prevents air and contaminants from entering the gas stream during