This product is used with helium, nitrogen, or argon gas cylinders. It is not tested for suitability with hydrogen.
Regulator types:
DIN6 - For use with helium, nitrogen, or argon gas cylinders
DIN1 - For use with hydrogen, methane, or 5% methane in argon gas cylinders
Please see the link: https://www.genstartech.com/sites/default/files/Specialty%20Gas%20Regulators%20%26%20Accessories.pdf