Aquascape Non-Woven Geotextile Underlayment is used to protect pond liner from rocks, roots, and other sharp objects that may damage the liner. The underlayment is light in weight, spreads easily, and has a non-slippery surface, making installation quick and easy. The soft, non-woven geotextile made from polypropylene allows for any gasses to escape properly, preventing future issues. Aquascape Non-Woven Geotextile Underlayment will last 20 or more years under your liner, ensuring years of trouble-free protection.