The SharkBite® radiant coupling is the easiest plumbing fitting to join radiant PEX tubing to a smaller NPT threaded pipe or fitting with no soldering, clamps, unions or glue required. It's as simple as inserting the pipe into the fitting deep enough to be sealed by our specially-formulated O-ring. Once inserted, the stainless steel teeth bite down and grip the pipe. This push-to-connect fitting is designed for radiant heating applications. It is rated up to 200 deg F and 200 psi.