TS16949:2009, ISO9001:2000, DOT certificate Double layer nylon tube reinforced tube :1).Material: PA, Nylon ,Polyamide2). ... surface,wear-resistant,resistant to high pressure,corrosion resistance,safe and reliable.6).Application: Fluid air,water, oil. Air brake ... Trailer air brake reinforced hose, air brake coil with double layerDouble tubing--Double layer nylon tube,double braided tube,reinforced tube