Connect 4 in. single-wall corrugated pipe to 4 in. sewer and drain (S&D) pipe or fitting with the National Diversified Sales 451 4" Black Spigot x Hub HDPE Corrugated Adapter. The drain fitting is also used to connect the 4 in. slotted pipe in the EZflow® Gravel-Free French Drain System (EZ-1001F) to 4 in. S&D pipe or fitting. This adapter is used to connect two different pipe types. The corrugated adapter is made of high-density polyethylene (HDPE). Meets applicable ASTM standards. For use in non-pressurized underground sewer and drainage applications; maximum working pressure of 5 psi. Hassle-free limited lifetime warranty guarantees the NDS product is free from defects—or we’ll replace it.