This kit’s brushes have super stiff and aggressive nylon bristles for the removal of stains on concrete, brick or stone. The large diameter brush is especially useful for larger de-scaling projects on metal surfaces or removal of loose paint. This brush has very stiff bristles and is NOT recommended for fabric, carpet, or where scratching could be an issue. Great for cleaning Barbecue Grills. This kit includes (4) brushes that all feature quarter inch quick change shafts for use with your own cordless drills (drill not included). Nylon bristles are safe to ingest unlike competitors metal brushes. These brushes will not rust like metal bristle brushes. Replaces Wire Brushes for Rust Removal, Loose Paint, De-Scaling, Graffiti Removal on Stone, Brick, and Masonry.