Pro-Edge Industrial push-in fittings, also known as Push-to-pull, push-to-connect, push-fit, or instant fittings, let you easily connect hoses in your compressed air system. These self contained fittings are a type of easily removed fittings that allow an air line to be attached. Simply push tubing in, no tools. Saves up to 75" of assembly time of standard compression fittings. These fittings act similar to the way regular compression fittings work, but use a resilient O-ring for sealing, and a grip ring to hold the tube in place. The main advantages of this technology over traditional soldered copper or glued plastic are that fittings can easily be unmounted and re-used, speed of assembly, assembly when wet and that the joints are still rotatable after connection. The issues that can cause joint failure are not pushing the pipe in far enough, not having a smooth round end to the pipe, too rough a pipe surface under the O-ring and detritus in the mechanism. Deburring the end of the pipe is vital to avoid damaging the O-ring on insertion, and the pipe surface under the ring must be smooth to get an adequate seal. The pipe end should be square so it sits against the stop in the fitting and does not cause turbulence. It is quite easy to push the pipe in only as far as the grab ring, or the O-ring, and not all the way to the stop. This fitting is all brass construction. The tube release is made of acetal resin. BunaN "O" rings standard. The threads are made of brass, with sealant, when applicable.