The ND ESW-80 Erosion Protection Grid is being used in extensive green roofs with a slope of 20 - 45 degrees. The cells of the ND ESW-80 Erosion Protection Grid are made of recycled polypropylene. Because of its size and shape the cells can be installed fixed to each other, which makes the construction very strong. In all the corners there have been screw holes applied to attach the sedum blankets. On the bottom there have been made cutouts so the water can flow through.