Tenders for Supply of Co2 Gas For Welding To Is 307/66 Reaffirmed In 1996 Grade I, Having Purity 99.7% Min. Co2 By Volume,. 1 Description For Parel And Snpd :- Co2 Gas For Welding To Is 307/66 Reaffirmed In 199 6 Grade I, Having Purity 99.7% Min. Co2 By Volume, In Firms Returnabel Cylinder. 2 Desc Ription For Mtn :- Refilling Of Co2 Gas For Welding To Is 307/66 Reaffirmed In 1996 Grade I, Ha Ving Purity 99.7% Min. Co2 By Volume. Cylinder Will Be Provided By Railways