Paper abrasive specific safety, silentness, work efficiency and durability to its maximum, a product without price difference with conventional whetstone.Made in Japan paper is used.High hardness material principally composed of zirconium oxide and alkali mixture Zirconia. Sharp shape and excellent durability.Grinding/polishing of stainless steel, difficult-to-cut materials, high hardness metals, heavy polishing of steel.Grain Size (#):80Outer Diameter x Blade Length x Hole Diameter (mm):100 x 15 x 15Max Working Rotation Speed (rpm):13600Blade Number (sheet):72Grinding Angle: 15 to 30Max Working Peripheral Velocity: 72m/s (4300m/min)