TS16949:2009, ISO9001:2000, DOT certificate Double layer nylon tube reinforced tube :1).Material: PA, Nylon ,Polyamide2).Size: ... .51.25 10×71.5 12×91.5 14×111.5 15×121.5 Inch: 1/4”,3/8”, 1/2”,5/8” etc.3). Working ... reinforced hose, air brake coil with double layerDouble tubing--Double layer nylon tube,double braided tube,reinforced tube