The pressure relief valves of imported high-pressure gas cylinders are mainly used for pressure regulation and relief of various gas cylinders, including oxygen cylinder pressure relief valves, hydrogen cylinder pressure relief valves, argon cylinder pressure relief valves, helium cylinder pressure relief valves and carbon dioxide cylinder pressure relief valves. The famous brands are Witton VTON, Jierui and Swagelok. Mainly made of stainless steel and brass, the inlet pressure is about 25Mpa, and the outlet pressure is about 0. 1-6Mpa.