... Pressure Vessel Co.,Ltd is a Professional Manufacturer of Seamless Steel gas cylinders, CNG-1 cylinder in Zhejiang, China .Zhejiang Tianen ... CNG cylinders :The specification of our CNG cylinder of Type-1 as following :Production standard : ISO11439 ,GB17258.Working ... .Out Diameter :232MM, 325MM, 356MM ,279MM,406MM .Wall thickness :5.5MM ,6.4MM,7.6MM,8.2MM, 8.8MM,9 ...