Silicone carbide impregnated in nylon bristles is self-replenishing as brush wears, offering unmatched value that outlast floor pad over 100 to one. That translates directly into time and cost savings. Featuring our water and chemical resistant Tuff-Block® to insure that the block last as long as the bristles for maximum life expectancy. Must be run in a wet environment. An excellent general scrubbing brush for frequent maintenance cleaning. Flexible enough for cleaning narrow grout lines & uneven surfaces. Grit Size: 180. Bristle Color: Blue; Bristle Diameter: .035. Pad Replacement: Blue.