... of high purity gas, such as oxygen,argon, nitrogen, CO2, helium, etc. ProductspuritystandardunitApplicationoxygen≥99. ... 5GB-T3863-1995bottle/cylinder Steel cutting, welding, flame processingnitrogen≥99 ... chemical industry, analysis Pure argon ≥99.99 GB/T4842-95Bottle Welding shielded welding, ...