Armor Shield floor pad for 21' x 43' oval for aboveground pools. Armor Shield provides an important protective layer between a vinyl swimming pool liner and its sand or soil base. Unlike traditional foam padding, Armor Shield is a Polypropylene Geotextile blend that minimizes cuts and punctures to the vinyl liner caused by rocks, roots, grass and even GLASS! Armor Shield also reduces convective heat loss and provides a comfortable floor pad for the comfort of pool goers.