The material of these metal files is diamond coating and carbide steel, which can increase the service life and strength of the product to a greater extent. Superior Performance: This needle file set has good heat dissipation performance, so the surface of the workpiece will not be blackened, discolored, or left behind due to overheating during grinding. There is little noise and dust during grinding, and it will not cause danger due to rust and falling off like a wire brush. The non-slip plastic handle is comfortable to hold. Widely Uses: Diamond files are most suitable for fine work and can be used for high-speed steel with a hardness of 69. It is particularly effective for metals such as stainless steel, titanium, and high-nickel alloys. Widely used in various molds, models, parts, handicrafts and other industries, such as: grinding, polishing, engraving, cutting, correction, etc. jade, ceramics, glass, crystal, metal, cemented carbide and other parts.