Bosch premium grade abrasives are constructed of high quality abrasive grains, bonding coats and backings for metal, concrete, masonry, pipeline, asphalt and stainless steel cutting. 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 * A24R-BF - Aluminum oxide grain, 24 grit grain size, in the medium range on the bond hardness scale. Resin bond and fiberglass reinforcing * AC24R-BF - Aluminum oxide / silicon carbide blending grain specially formulated for ductile cutting, 24 grit grain size, in the medium range on the bond hardness scale. Resin bond and fiberglass reinforcing * C24R-BF - Silicon carbide grain, 24 grit grain size, in the medium range on the bond hardness scale. Resin bond and fiberglass reinforcing * CS30Asphalt-BF - Silicon carbide grain specially formulated for use with asphalt, 30 grit grain size. Resin bond and fiberglass reinforcing