Coated with zirconia alumina to stay sharper longer. The abrasive grit continually fractures to produce new, sharp cutting edges. This abrasive is great for aggressively removing material from steel and wood, and it lasts longer than aluminum oxide. Press onto a compatible sanding tool or backup pad (sold separately); peel off to remove. Also known as PSA discs. To maintain strong adhesion, clean the pad surface with mild alcohol before applying. Do not use aggressive cleaning solvents such as MEK or acetone, which can damage the adhesive.