* AS60INOX-BF - Aluminum oxide grain specially formulated for use with stainless steel, 60 grit grain size. Resin bond and fiberglass reinforcing* AS46INOX-BF - Aluminum oxide grain specially formulated for use with stainless steel, 46 grit grain size. Resin bond and fiberglass reinforcing* C60R-BF - Silicon carbide grain, 60 grit grain size, in the medium range on the bond hardness scale. Resin bond and fiberglass reinforcing* Easy-to-read labels are incorporated into the manufacturing process and therefore remain intact throughout the life of the wheel* While some manufacturers use recycled grains, Bosch uses only superior virgin grains made to exact specifications. Carefully formulated resinoid bonds are applied to meet the unique specifications of each wheel* Multiple layers of long, stranded fiberglass are woven to form an exceptionally strong reinforcement layer specific to the application