Armor Shield Floor Pad provides an important protective layer between a vinyl swimming pool liner and it's sand base. Unlike traditional foam padding, Armor Shield is a Polypropylene Geotextile material that prevents cuts and punctures to vinyl liners caused by rocks, roots, grass and even glass! Armor Shield Padding is super tough, but also adds a layer of cushioning that will eliminate footprints from forming. Simply place Liner Armor Shield under your new vinyl liner during installation. It's durable material resists acids, alkalis, salt, oils, mold & mildew. Easy to install no wrinkles!