Add years of life to your pool liner! Using Gladon Waveless, high quality Pool Wall Foam with your 12'x21' oval above ground swimming pool protects against punctures to your pool liner. Create a smooth wall surface with this closed-cell foam padding that helps prevent rust, corrosion and other wall degradation. It keeps your liner looking like new for years to come. Wall foam is a 1/8" thick foam mat that protects your liner from constant friction against your pool wall, preventing tears or punctures. Pool Wall Foam is also ideal for use with pool heaters and solar covers since it adds insulation to your pool to keep the water warmer and save energy.