6", Green, Square Structural Foam Polyolefin Grate, With A Diagonally Converging Pattern & UV Inhibitors, 10.40 SQIN Open Surface, 13.62 GPM, Fits 3" Or 4" Sewer & Drain Pipe, 3" Or 4" Corrugated Pipe & 3" Or 4" Triple Wall Pipe, Loads Of 1-60 PSI, Recommended For Pedestrian, Bicycles & Wheel Chair Traffic.