4"x100' Corrugated Drain Tubing. It is made of polyethylene, has an outside diameter of 4 inches and an inside diameter of 4 inches. This single wall corrugated HDPE pipe is ideal for drainage projects where flexibility, lightweight and low cost are important. It has kept farms, golf courses, parks, and playing fields dry for decades by channeling away excess underground moisture. Homeowners find it to be an economical, easy-to-install solution to all kinds of residential storm water drainage problems downspouts run offs, foundation and window well drains, driveway culverts, and wet spots on the lawn. It is also used for highway edge drains, culverts, and other construction applications where economy and durability are important.