... take the most advance technology in copper process, Rolling-Casting. Inner-grooved Copper Tube is of high cleanliness and ... super brightness of inner and outer surface. It ... pin holeStandardAISI, ASTM, BS, DIN, JIS, ENMaterialRed copper, brass copper, and so onOutside Diameter4mm~60mmWall Thickness0.25mm~5.0mmLengthas ...