This product features rounded bottom corners for enhanced safety and is stamped from a single sheet of steel. Its bright finish reflects light into the basement, improving visibility. The flanges include holes for bolting the unit securely to the wall. Deep corrugation adds stiffness, helping the unit withstand backfill pressure. For optimal performance, backfilling should be done gradually to avoid excessive pressure against the wall. The dimensions are 19-1/2 inches in width and 10 inches in depth.