Connect 3 in. Sewer and Drain (S&D) pipe to 4 in. S&D pipe with the National Diversified Sales 4P07 3" x 4" White Hub x Hub PVC S&D Increaser/Reducer Coupling. The coupler also connects 3 in. S&D pipe to select drainage products compatible with 4 in. S&D connections as well as 4 in. S&D pipe to select drainage products compatible with 3 in. S&D connections; drainage products include channel drain outlets and pop-up emitters. This coupling connects two different pipe diameters of S&D pipe. The S&D Increaser/Reducer Coupling is made of polyvinyl chloride (PVC) and makes a Hub X Hub solvent-weld connection. 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.