Use ferrules to create a permanent connection between your air- and water-hose and barbed hose fittings. You will need a hose crimper (sold separately) for installation.Brass and aluminum ferrules have good corrosion resistance. Choose a ferrule with an ID no more than 0.025" larger than your hose OD (measured with the fitting installed); also make sure the ferrule is at least as long as the barbed end of your fitting.