Pneumatic tubing fittings secure tubing to ports, prevent leaks, and maintain pressure. They have two connection ends that come in a large variety of connection types. These include push-in to flanged, compression-nut to threaded, and barbed to barbed. Threaded connection ends come in male or female forms. Pneumatic tubing fittings are typically made of strong, durable metals such as brass or stainless steel that resist corrosion and wear.