Rego Check Valve New Brass Body CG500B - Cryogenic Inline 1/2" F.Npt 3000 PSI For Tank One directional flow indicated by arrow on body. Large Cv for high flow capability and low pressure drop. 1 psig opening pressure. (We also carry all rego valves and cylinder accessories) Cleaned for use in oxygen service per CGA G-4.1 Working temperature: -320 F to +165 F for metal seats; -20 F to +165 F for soft seats.