Silicon carbide grain for fast cut rate and finest finish.Provides best durability, stock removal, and finest finish for increased productivity.Available in two densities.Medium Density: Comparable to competitive 8SF , Excellent starting point for general purpose deburring, blending, and weld polishing.Hard Density: Comparable to competitive 9SF products, Excellent for aggressive deburring, blending., Convolute wheels are constructed by wrapping non-woven nylon, impregnated with abrasive grains, around a hard core to form a homogenous wheel.Dense, non-woven construction for long lasting wear and high edge durability.Non-metallic for no workpiece contamination.Smear-resistant formulation to greatly reduce the possibility of smearing.NOTE: Wheels must be run in the direction of the arrow as indicated on the wheel..For mounting flanges and reducing bushings see Accessories.