Use Red Heat Q955 CA fine grit screen flooring sanding disc for fine grit sanding jobs on concrete or hard woods. A tough F-weight screen backing gives the disc flexibility and shock absorption ideal for tough surfaces. This screen pairs with the patented 100 percent ceramic alumina grain for a consistent cut and finish rate throughout the screen’s life, which is two to three times longer than silicon carbide discs. The disc minimizes swirl marks and eliminates the risk of burnishing the wood while producing a finer scratch pattern than silicon carbide.