Black Oxide Step Drill Bit Set with Titanium Drill Bit Set (33-Piece). MILWAUKEE Black Oxide Step Drill Bits are perfect for drilling large and small diameter holes in steel and plastic. The step drill bits give jam-free performance optimized for cordless drills at 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. Milwaukee SHOCKWAVE Impact Duty Titanium Drill Bits with REDHELIX are engineered for impact drivers and drills. The drill bits are designed with Variable Helix featuring an aggressive 35° Helix Angle ending at 15°. This allows for Rapid Chip Removal, limiting heat buildup to Stay Sharper Longer. The QUAD EDGE tip delivers a precision start and four cutting edges to create smaller chips for faster removal and less heat leading to longer bit life. The bits also feature an internal ENHANCED TAPERED WEB that greatly increases their strength, reducing premature breakage. Ideal for various applications including but not limited to wood, plastics, and metals, Milwaukee REDHELIX Titanium Drill Bits provide up to 5X life vs black oxide drill bits.