Nylo-Seal type "NNR" semi-rigid natural color tubing is made of Nylon-II and is far superior to other types of Nylon tubing. It does not depend on moisture for flexibility and does not become brittle. It has excellent resistance to flexural fatigue and can be used where there is vibration or tube movement. Self-extinguishing under A.S.T.M. Test D635-44. NNR Tubing is rated to 1500 lbs. and is excellent for instrument lines and other low pressure applications. Use NBR tubing (2500 lb. rating) for hydraulic brake lines after verifying it is appropriate tubing for your application.