Porcelain stoneware tiles are glued to a thermoplastic tub support using a special adhesive under high pressure. In the tub support, under the porcelain stoneware tile, three parallel inserts made of galvanized steel run along the entire length of the board for reinforcement. The bottom of the board is grooved for attachment to the GRAD rail system with GRAD clips - DEX Easy System. The result is a quick installation, invisible fastening, perfect alignment and high quality materials.