Milwaukee® step drill bits with JAM-FREE performance feature a dual-flute design delivering upto 2X faster hole times, upto 4X longer life and upto 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. The 3-flat Secure-Grip™ shank ensures a solid connection with the drill chuck. The #1 Step Drill Bit has 13-hole sizes in 1/32 in increments ranging from 1/8 to 1/2 in JAM-FREE Performance in high speed with most professional 18 V cordless drills Lithium-Ion battery technology. Milwaukee® Step Drill Bit, Imperial, #1 Letter/Wire, 1/8 in Diameter Minimum Hole, 1/2 in Diameter Maximum Hole, 13 Steps, 13 Hole, 2 Flutes, 1/4 in Shank, 3-Flat/Reduced Shank, HSS Cutting Edge, HSS, Black Oxide, Applicable Materials: Metal and Plastic