high purity gases, argon, oxygen, hydrogen, nitrogen, helium ... welding, flame processingnitrogen≥99.5GB-T3864-1996bottle/cylinderReplacement gas and protection gas for chemical industry, metallurgy, and electric industry.hydrogen ... cuttingpure hydrogen≥99.99GB/T7445-1995bottle/cylinder Raw material gas, high-altitude weather balloon used in chemical industry.pure Helium≥ ...