Tools Drill Bit Set, Cobalt Alloy Steel, Jobber, Fractional, 21-Piece (63221). Drill bits are made of M-42 5% Cobalt Alloy Steel high-speed steel for super abrasive resistance in tough metals. 135° split point reduces feed pressure for easy penetration without work hardening. Each drill bit has a heavy-duty spiral flute design that produces faster chip ejection. Shorter cutting lips reduce torque for drilling in high-tensile-strength materials. Cobalt Alloy Steel drill bit set comes in a metal index case. Drill bits are made of M-42 5% cobalt high-speed steel for super abrasive resistance in tough metals. Cobalt drill bit set comes in a metal index case. This IRWIN Cobalt Alloy Steel High-Speed Steel Drill Bit Set includes drill bits made of M-42 5% Cobalt Alloy Steel high-speed steel for super abrasive resistance in tough metals. The 135° split point reduces feed pressure for easy penetration without work hardening, while the heavy-duty spiral flute design produces faster chip ejection. These versatile drill bits come in a metal index case for easy transport and organization. Irwin Industrial Tools 63221 Cobalt Fractional Straight Shank Jobber Length – Metal Index – 21-Piece Set. Irwin offers a complete line of Metal Twist Drill Bits, including Black Oxide, Turbo Point, Titanium Nitride and Cobalt Drill Bits. Please look through our selected quality items to see if you can find what you are looking for or to discover new and exciting things. But we will make sure you receive it in perfect condition(in case of damage on arrival let us know within 2 days for a solution/replacement). Your satisfaction is our #1 priority!