Armed with an exceptionally sharp, 100-percent ceramic alumina grain, Red Heat H955 CA medium grit paper H&L floor sanding discs deliver cleaner scratch patterns and smoother finishes than any other products. They make an excellent choice for large sanding jobs on hard aluminum oxide finishes and the hardest woods and can also be used on concrete. The stiff, ultra-tough, paper F-weight backing allows aggressive cutting with minimal tearing and snagging. These discs eliminate color transference for maximum color consistency.