29PCS HSS Cobalt Drill Bits Set 1/16″ to 1/2″ with Three Flute for Hard Metal, Hardened Stainless Steel and Cast Iron. UNIQUE 3X FLUTE DESIGN – three flute patent design drill bit clears chips and particles faster, provide you with more efficient drilling experience. 4X LIFESPAN MATERIAL – Made from industrial grade M35 high-speed steel with 5% cobalt provides hardness for wear resistance, withstands max 1100 degreeF. MULTIPLE APPLICATION – Ideal for drilling in heavy-duty tough metal, including hard abrasive alloy metal, hardened stainless steel or cast iron. SMOOTHLY DRILLING – 135-degree split point tip & twist design increases cutting speed with self-centering and prevents skating starts or walking. 29PCS DRILL BIT SET – Metal index case with size chart for easy bit access and identification. Includes drill bit sizes 1/16-inch to 1/2-inch in 1/64-inch increments. The 1/8-inch to 1/2-inch bits are specially designed three flute bits, while the four smaller bits from 1/16-inch to 7/64-inch are two flute bits.