Bulldog Gold's grip (hook-and-loop) and PSA sanding discs have a special sharp, durable aluminum oxide grain that gives you a fast and exceptionally long-lasting cut. Durable aluminum oxide, combined with urea resin over glue bonds, and an open coat create a high performance sandpaper that's the envy of the industry. These discs come on a B weight backing, giving the disc better edge wear and wearability.