NDS 16 3" Green Plastic Round Grate, Connects to 3" Drain Pipes and Fittings drains light flows of stormwater from small lawns, landscaped areas, patios, and walkways. Leaves and debris are blocked from entering the drain pipe to prevent it from clogging and backing up. Grate has an open surface area of 2.6 sq. in. and flow rate of 8 GPM. The 3 in. Round Grate connects to 3 in. sewer and drain pipe & fittings, 3 in. single-wall corrugated pipe, and 3 in. triple-wall 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.