5 different 6 mm shaft grinding heads: spherical, conical, cylindrical, tip, conical. Burr set made of high-speed steel, robust and durable, good wear resistance and heat resistance, so that its hardness can reach up to HRC70. Suitable for deburring and polishing iron, steel, carbon steel, alloy steel, stainless steel, copper, aluminium and other metals as well as marble, jade and bone.