Soft, flexible sheet perfect for polishing contours and interior curves. The grits are color-coded for easy selection. Sold in a pack of 5. Size is 8-1/2" x 11". 3M ALUMINUM OXIDE is widely used as a coarse and fine abrasive. The most common form of aluminum oxide is called corundum. Its low heat retention makes it ideal for grinding. 3M uses sharp, resin bonded aluminum oxide grain that provides a fast, continuous cut and long-life performance. The abrasive is uniformly applied for a fine, consistent finish.