... Tianen CNG cylinders :The specification of our CNG cylinder of Type-1 as following :Production standard : ISO11439 ,GB17258.Working Pressure :20Mpa ,Testing ... ,150L.Out Diameter :232MM, 325MM, 356MM ,279MM,406MM .Wall thickness :5.5MM ,6.4MM,7.6MM,8.2MM, 8.8MM,9 ... inquiry us . We will reply you immediatelly . CNG Cylinder of Type 1