Scuff Balls are manufactured from synthetic fibers, bonded together with formulated resins and impregnated with mineral grain. Scuff Balls are designed for a broad range of jobs including light duty cleaning, polishing scuffing, finishing and for heavy duty jobs including paint, rust and corrosion removal. These tough synthetic fibers will not rust, they can be used for dry scuffing and finishing or may be used with water or chemical solvents, and designed for continous use. Works with most drills and pneumatic grinders. Made in USA. 4" Scuff Ball Maroon medium compares to #00 steel wool, Aluminum Oxide grain.