3X Abrasive Sheet, Paper Backing, Aluminum Oxide Load resistant stearate coating, fiber reinforced backing, and high quality zirconia alumina combine to give 3X the performance of typical aluminum oxide paper sheets. Zirconia alumina is self-sharpening and durable, allowing for a faster cut rate than aluminum oxide. Open-coat construction offers more flexibility and clog resistance than a closed-coat sheet. Water-based stearate coating resists loading for extended abrasive life. Paper backing is flexible, and offers a more consistent finish than a cloth or fiber backing, while being thicker and more durable than a polyester film backing. 20 pack. 80 grit.