Optimum for grinding process of hardened materials such as carbide alloy, hardened steel, ceramics, glass, reinforced plastic.Sharpness of diamond abrasive grains will last until the end.The blade metal has elasticity and fits the work material.Optimum for use in burring finish, cutting, modification and rubbing etc.Type:8 Piece SetShape:Triangle (width) 4.5Total Length (mm):180Blade Length (mm):70Handle Shape:RoundPrecision Type (#170)8 pieces set, 10 pieces set is a common name expressing the size of a file, it does not mean that it actually contains 5 pieces, 8 pieces, 10 pieces, 12 pieces.