Series 5525 Carbide Ratio Drill Metric sizes 3.00mm to 20.00mm Carbide Self centering 12xD 135 point angle Nano-FIREX Coating Ultra-finest grain-solid carbide, according to factory standard, type RT 100 U. Fire coated surface, right cutting with special point geometry and ratio point thinning.Normal rake angle Application: For accurate holes with narrow tolerances and good surfaces. Suitable for drilling deep holes up to 12 x D with high cutting values. Particularly suitable for economical production of deep drill holes in steel, castings and non-ferrous metals. Note: The drills can be sharpened and recoated several times.