6", Sand, Round Structural Foam Polyolefin Grate With UV Inhibitors, Open Surface Is 9.10 SQ IN And Has A Flow Rate of 11.92 GPM, Fits Spee-D Basin, 6" Sewer & Drain Pipe & Fittings, & 6" Corrugated Pipe, Recommended For Pedestrians, Bicycles, & Wheel Chair Traffic.