Viair Premium Push-to-Connect Fittings are made from nickel-plated brass for durability and corrosion resistance. These fittings use an internal collet and an external push-button to connect quickly and effortlessly creating a leak free connection every time. Available in 1/8", 1/4" and 3/8" outer diameter sizes, these fittings come in a variety of different configurations to suit any custom air line project. All Fittings are DOT approved and have a maximum working pressure of 200 PSI.