1)Seamless steel tube per ASTM A106B 2)Size: 1/4"-28"*SCH20\30\ ... STD\60\80\100\120\140\160\XXS steel tube per ASTM A106/A53/API-5L.GR.B 2) Application ... usual structure and machines 3) Model No.: ASTM A106 grade A/B, API 5L, X52, X42, ST52, K55, STK490, STPG, C20 ... standards implemented: DIN, JIS, ASTM (ASME),etc 1)Seamless steel tube per ASTM A106B2)Size: 1/4"-28"*SCH20\30\STD ...