The 42” x 125’ x ⅛” Wall Foam Blue provides reliable protection and insulation for pool liners in in-ground and above-ground installations. Made from closed-cell polyethylene, this 1/8" thick blue foam creates a smooth, cushioned barrier between the pool wall and liner to prevent rust, corrosion, and punctures. By reducing heat loss through the pool walls, this foam enhances liner longevity while improving overall energy efficiency.