Bostik J115 Flexible Smooth Finish Grout is a professional quality, cementitious polymer modified grout for walls and floors. It is formulated to provide narrow and wide joints. Bostik J115 Flexible Smooth Finish Grout is an easy clean off, non slump formulation and dries to a very hard finish.Suitable for use with a variety of tile types including ceramic, porcelain, natural stone, mosaic, marble and quarry tiles. It is suitable for joints between 2mm and 15mm for both interior and exterior use.