MacCourt window well covers are designed to protect your basement from water, keep your wells free of debris and improve your basement's energy efficiency. They protect your basement by preventing water from entering through the window wells while keep your wells free of animals, leaves and other debris. Made of clear plastic to let natural light into your basement they also improve your basement's insulation. This cover fits over window wells of 64" or less in length and projecting 22" or less from the house. Inside dimensions are 61"W x 20-3/4"D x 16-3/4"H, while outside dimensions are 66-1/2"W x 21-3/4"D x 20"H.