... insulating DescriptionWe take the most advance technology in copper process, Rolling-Casting. Inner-grooved Copper Tube is of high cleanliness and super brightness ... , 100% no pin holeStandardAISI, ASTM, BS, DIN, JIS, ENMaterialRed copper, brass copper, and so onOutside Diameter4mm~60mmWall Thickness0.25mm~5.0mmLengthas your ...