1. Premium material, made of high quality tungsten steel. Used on wood, iron, steel, carbon steel, alloy steel, stainless steel, copper, aluminum and other metals as well as marble, jade, bone, etc. 2. All cutters have 1/8" shank - compatible with most rotary tools and die grinders. 3. Highly recommended for DIY, arts and crafts, hobby, home repairs, jewelry, stone working, modeling and more. 4. 10 different cutters including: ball, cone, cylinder, needle point, taper point, etc. to meet most of your drilling needs, suitable for drilling, engraving, carving, polishing, beveling, chamfering, grooving, reaming and hollowing. 5. The rotation speed of rotating tools is generally 6,000-50,000 rpm, which ensures long service life and avoids rotation inefficiency. Easy cutting, safety and durability.