TS16949:2009, ISO9001:2000, DOT certificate Trailer air brake reinforced hose :• Material:PA,PU,double nylon tube• ... (Polyurethane) TubeTubing -- PU (Polyurethane) air brake coils, spiral hoseDouble tube--Trailer air brake reinforced hose, air brake coil with double layerDouble ... tubing--Double layer nylon tube,double braided tube,reinforced tube Trailer air brake reinforced hose