The IRWIN® Metal Countersink Drill Bit Set features precision ground 82 tips for countersinking most machinable metals, wood, and plastic. Made from industrial grade high-speed steel for increased durability, each countersink has a black oxide coating to resist corrosion and a five-flute design that reduces vibration for smoother drilling and an extended life. Set includes 1/4", 3/8", 1/2", 5/8", and 3/4" countersinks, and a drawer Case