The "Ultra Protect" basement window well covers are designed with "Safety" and "Security" for your home and family in mind. These professional grade lightweight basement window well covers are built using clear impact resistant, UV resistant, polycarbonate sheet plastic and structural grade aluminum. Installing an "Ultra Protect" basement window well cover over your open basement window well minimizes the risk of persons or animals falling into deep, uncovered, unprotected basement window wells, preventing possible serious injury. When properly installed using our "Well Clip" mounting hardware (included) these covers will support a minimum of 250 lbs. The model SR400 (41 in. x 19 in. semi-round) window well cover is designed for use over typical corrugated steel window wells. After installation this cover can be trimmed (if needed) to the profile (plus up to a 1 in. overhang around the perimeter) of any typical semi-round window well by using an ordinary jigsaw equipped with an aluminum cutting blade (8 to 12 teeth per in. blade for best results) making for a custom fit window well cover.