This 1mm round Ruby Midget File is invaluable for high detail and ultra-precision work. Break it off and cement onto a holder or use with a pin vise.  Ruby Stones are the ideal choice for deburring, blending, dressing, and fine polishing of molds & dies made of hard metals such as hardened tool steel, carbide and surgical stainless steel. Jewelers use them for sharpening of carbide and high speed steel engravers and other tools.  Measures 1mm round x 50mm long (approx. 0.04" x 2") all dimensions have tolerance of ±0.1mm.  Fine grit only.  Made in Germany from pure, sintered crystals of synthetic ruby. No bonding material is used, so these stones and files are extremely hard and resistant to changes in shape. This is particularly important for quality precision grinding and finishing. In addition, since Degussit Ruby Stones and Files feature outstanding resistance to wear, they are more economical to use than other comparable tools. Use dry or with Gesswein Stoning Oil to grind, touch up or debur steel and carbide parts. Also recommended for use on materials such as glass, quartz and porcelain.