The tube is using material of JIS STKM 13C. High yield strength, better mechanical property and good weld-ability. The internal grinding & external Hard-Chrome platting can meet with International standart.The ground inside surface and external Hard-Chrome-Plate after grinding that tolerance meet with international standart

• External Diameter Accuracy : H7,H8,H9
• External Diameter Accuracy : f8
• Internal Roughness : 0.8 ~ 3S
• Hard Chromium Plate Thickness : 20 5%