This Tru-Flate 21-535 bushing is suitable for connecting two pipes or hoses with different diameters. It is made of brass for resistance to corrosion. It has a 1/4" female National Pipe Thread (NPT) connection on one end for connecting to a male pipe or hose fitting and a 3/8" inch male NPT connection on the other end for connecting to a female pipe or hose fitting. This bushing is precision machined for a longer life and better performance, and is suitable for use with compressed air lines.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, PBT (polybutylene terephthalate), 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.Plews & Edelmann manufactures automotive and pneumatic hose, lines, reels, accessories, fittings, and lubricants under the Edelmann, Amflo, Omega, LubriMatic, and UltraLube brands. The company, founded in 1909, is headquartered in Dixon, IL.