The MILWAUKEE® Step Drill Bits with JAM-FREE Performance feature a dual-flute design delivering up to 2X faster hole times, up to 4X longer life and up to 50% more holes per battery charge than competitors. The Rapid Strike™ tip allows for a fast and accurate start that generates less heat, resulting in longer bit tip life. Black oxide coating alsoenhances durability, hole quality and bit life. For user convenience and accuracy, each bit has laser-engraved reference marks you can see while drilling. The 3-flat Secure-Grip™ shank ensures a solid connection with the drill chuck. The Step Drill Bit 6-Piece Set includes bits #1, #4, #6, #7, #8 and #9. Jam-Free Performance in high speed with most professional 18 volt cordless drills with lithium-ion battery technology. The MILWAUKEE® RED HELIX™ 29PC Cobalt Drill Bit Set is engineered for extreme durability and long life in hard metal applications. The QUAD EDGE™ tip delivers a precision start and features four cutting edges to create smaller chips for faster material removal and less heat leading to improved performance. Designed with a VARIABLE HELIX™ flute that begins with an aggressive 35° helical angle and ends at 15° for rapid chip removal. The bit also features an internal thicker tapered web that greatly increases strength, reducing premature breakage. Ideal for various tough metal applications including but not limited to Stainless Steel, Cast Iron, and Thick Metal.