Use the National Diversified Sales 9P11 4" White PVC Round Grate on patios, decks, and around pools to prevent costly water damage. Drain light flows of excess surface water and block leaves and debris from infiltrating the pipeline. Grate has an open surface area of 3.9 sq. in. and flow rate of 12 GPM. The 4 in. Round Grate connects to 4 in. Sewer and Drain (S&D) fittings such as an adapter to connect to drain pipe. The Drain Grate, also known as a drain cover, is made of polyvinyl chloride (PVC) treated with UV inhibitors. 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.