The 10 piece MILWAUKEE Step Drill Bit Kit is perfect for drilling large and small diameter holes in steel and plastic. The step drill bits give jam-free performance optimized for cordless drills in high speed. The dual-flute design creates quicker holes, longer life and more work time per battery charge. The Rapid Strike tips facilitate fast, accurate starts that generate less heat and give longer bit tip life. Black oxide coating enhances the step bits' durability, hole quality, and bit life. Each bit has laser-engraved reference marks for ease of use and convenience while drilling. The 3-flat Secure-Grip shank ensures a solid connection with the drill chuck.