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. Ideal for drilling small and large-diameter holes in steel and plastic, these bits are Optimized for Cordless Drills in High Speed. The Rapid Strike tip allows for a fast and accurate start that generates less heat, resulting in longer bit tip life. Black oxide coating also enhances durability, hole quality and bit life. For user convenience and accuracy, each bit has laser-engraved reference marks you can see while drilling.