... 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 Pressure :20Mpa ,Testing Pressure :30MPa ,33.4Mpa.Water Capacity :20L, 25.5L, 28L, 34L,50L ,57L ,65L, 70L ,75L, ...