This Eaton Weatherhead 1862X4 brass union with internal O-ring is a push-to-connect-type fitting for joining nylon air brake lines. A female push-to-connect-type mechanism with an O-ring at each end of the union fits over 1/4" outside diameter (OD) nylon tubing, and the O-ring forms an air tight seal. The fitting is made of CA360 brass for corrosion resistance, ductility at high temperatures, and low magnetic permeability. It has a working pressure of up to 150 pounds per square inch (psi). This union fitting meets U.S. Department Of Transportation (D.O.T.) FMVSS 571.106 air brake specifications and is suitable for use in air brake lines, such as those in buses and trucks.Tube fittings are components used for connecting, branching, terminating, and changing the direction of tubing in pneumatic and hydraulic systems. They are made of brass, stainless steel, polybutylene terephthalate (PBT), and other materials that resist corrosion and wear. Tube fittings have various types of connections, including threaded, welded, barbed, and push-to-connect (also called one-touch). Push-to-connect connections do not require tools or sealants. Tube fittings are used in various applications, including machine tools, airplane and truck controls, and automated production lines, among others.Eaton manufactures electrical, hydraulic, and mechanical power equipment. The company, founded in 1911, is headquartered in Dublin, Ireland.