These long lasting abrasives are comprised of a combination of ceramic and aluminum oxide grit materials, making them extremely aggressive, offering outstanding productivity. Bona 5" Green Ceramic Abrasive Discs (8-hole) consist of a combination of ceramic and aluminum oxide grains, allowing for an aggressive abrasive that provides extended product life and results in a quality surface for finishing. Key benefits: Cuts 30% faster than any other competitive ceramic abrasive, Lasts up to 50% longer than any other competitive ceramic abrasive.