Aluminum Oxide - Closed: Aluminum Oxide grain with full resin bond, "X" weight with cotton/polyester backing - waterproof and closed coat.
Used for aluminum, steel, composite, and solid surface. Excellent all purpose abrasive.

Zirconia: Made from blue premium Alumina Zirconia grain, with a "Y" weight polyester backing.
Full resin bond, closed coat and waterproof. Used for sanding stainless steel, aluminum, titanium, mica nickel, alloys and hardwood.