Nova Swiss manufactures high-pressure needle valves and high-pressure couplings in pressure classes from 10,000 PSI to 160,000 PSI.
And tubing.   Their fittings and valves are used together with similar products from other suppliers.   All parts for pressure classes below 30,000 PSI are supplied to the NACE standard.
Material certificates are standard on Nova Swiss valves, and they can supply traceable certificates for all parts in the valves.
Apart from this, each part is etched with a part number and material code, also on the collar and gland for the fittings.
Product solutions for Hydrogen, see our website about hydrogen production, transportation and filling.   More info: www.novaswiss.com