Premixed black grout Safe to use Water based, non-sanded, non-cement based formula Premixed grout is for grout lines of up to 1/8-inch Perfect for mosaic projects Premixed black grout Water based, non-sanded, non-cement based formula Premixed grout is for grout lines of up to 1/8-inch Perfect for mosaic projects Mosaic Mercantile's Pre-mixed Tile Grout is intended for light-duty indoor applications where the space between tiles is 1/8 (3 mm) or less. This water-based latex grout is already mixed to save time and measuring.