For applications with plastic, cast iron, copper, and steel, this Fernco 105644RC flexible repair coupling allows you connect 4" pipe to 4" pipe so that you can extend the line. It can be used in a number of plumbing applications, including waste, sewer, drain, etc., but don't forget vent piping. The clamps are stainless steel and will help ensure the structural integrity you want and expect out of Fernco products. When you shop PlumbersStock.com for your rough plumbing items, you can save big, and it's no exception with this Fernco flexible 4" to 4" fitting (1056-44RC). Find out for yourself why so many choose us as their Fernco parts dealer. Save on all your fittings and all your pipe to pipe connections for plumbing repairs right here. This PVC fitting is GSA approved.