Medallion Pools OCFG1442 Outside Corner Filler for 42" Square Walls 14ga Galvanized Steel - Create the inground pool of your dreams with this Medallion Pools Outside Corner Filler for 42" Square Walls. It is constructed of durable 14-gauge galvanized steel. Steel is an ideal choice for inground pools due to its natural malleability. Steel is able to handle changing conditions while remaining strong and intact.