To achieve high corrosion resistance and wear and abrasion resistance in a conduit especially when the conduit consists of a polyamide 12 layer extruded/coated with a polyamide layer, and when a surface processed coat without chromium, especially a phosphate processed coat and/or primer coat is inserted between an aluminum coat and the polyamide layer.

The conduit for the fluid used for motor vehicles, in particular, the fuel and hydraulic liquid, comprises a metal inner tube, the aluminum coat formed on the outer surface of the inner tube, and the polyamide layer connected to the aluminum coat.