Series Tubing O.D.
Metric size		 Tubing O.D.
Inch size		 Color Fluid
TU/TIUB φ2，φ4，φ6，φ8
φ10，φ12，φ16		 φ1/8''，φ3/16''，φ1/4''
φ3/8''，φ1/2''		 Black, White, Red,
Blue, Yellow, Green,
Clear, Orange, and
more (Total 29 colors		 Air, Water