National Diversified Sales D8 8" Ductile Iron Round Duracast Grate, Connects to 8" Spee-D Basin & Drain Pipes is made of solid ductile iron and has an H-20 load rating. Open surface area of 14.0 sq." and 43 GPM flow rate makes it ideal for draining moderate flows of runoff on parking lots, driveways, plazas, courtyards, lawns, and landscaped areas. The 8" Round Grate in ductile iron connects to 8" sewer and drain pipe and 8" single-wall corrugated pipe for a soil-tight fit. Iron grates will rust over time, forming a protective iron-oxide patina that ages from red-orange to a deep, rich brown. NDS grates are lightly painted black to inhibit rust formation for shipping and storage purposes. Hassle-free limited lifetime warranty guarantees the NDS product is free from defects—or we’ll replace it.