... , DOT certificate Air brake coil with double layer nylon :• Material:PA,PU,double nylon tube• Hose size(OD*ID): ... M16,M18 ,M22 ,1/2"fittings etc. or no fitting• Type:European style, American style, ordinary type-----------------------------------------BlueMob.: + ... reinforced hose, air brake coil with double layerDouble tubing--Double layer nylon tube,double braided tube,reinforced tube Air brake coil ...