NIBCO PCH600-DS 11/4 PRESS X PRESS COUPLING.NIBCO press fittings are the fastest, easiest way to join copper tubing systems. NIBCO PressG fittings are designed to join with seamless copper water tube in residential and commercial gas and compressed air systems. The press fittings can also be installed underground. NIBCO PressG fittings are user friendly, quick and easy to install. When properly crimped a unique “N” witness mark is clearly visible.