TS16949:2009, ISO9001:2000, DOT certificate Trailer air brake reinforced hose :• Material:PA,PU,double nylon tube• ... ,70,60,50mm etc.• Helix turns/coil:12,16,18,20,22,24,26,28,30 coils.etc.• Stretched length:5m ... (Polyurethane) TubeTubing -- PU (Polyurethane) air brake coils, spiral hoseDouble tube--Trailer air brake reinforced hose, air brake coil with double layerDouble ...