Custom part, made in USA. This adaptor fitting installs into any 57/58 Eldorado Brougham air suspension part that had the copper tube and steel nut. This brass fitting accepts the o-ring and will screw into any part (air domes will have to remove the schreader check valve). The back side of the fitting is tapped for 1/8" NPT so you can install a modern air hose quick connect fitting. Size of your choice. This will not damage the treads of your original valve, air dome, etc and offer a easy way to run modern hose from point to point. Includes new Viton O-Ring seal on each fitting.