The color tag on the outside of the Agilent flexible stainless steel tubing indicates the internal diameter (ID) of the tubing: RED indicates an internal diameter of 0.12 mm or 0.005 inches. GREEN indicates an internal diameter of 0.17 mm.or 0.007 inches. BLUE indicates an internal diameter of 0.25 mm or 0.010 inches. ORANGE indicates an internal diameter of 0.50 mm or 0.020 inches