NDS 1250 12" Green Plastic Round Grate, Connects to 12" Drain Pipes prevents the elements from infiltrating your system. Grate has an open surface area of 46.0 sq. in. and flow rate of 141 GPM, and drains heavy flows of stormwater from lawns, landscaped areas, parks, and courtyards. The 12 in. Round Grate connects to the 12 in. sewer and drain pipe and 12 in. single-wall corrugated pipe for a soil-tight fit. Made of high-density polyethylene (HDPE) treated with UV inhibitors. Hassle-free limited lifetime warranty guarantees the NDS product is free from defects—or we’ll replace it.