Milwaukee THUNDERBOLT™ 21-PC Black Oxide Drill Bit Set is engineered for extreme durability, heavy-duty performance, and long-lasting use. These drill bits feature a thicker core web than standard bits to protect against side-load breakage, providing increased strength for demanding tasks. The 3-Flat Secure-Grip™ shanks ensure a firm, wobble- hold in drill chucks, enhancing precision during drilling. Designed with a special parabolic flute, these bits clear chips quickly, while the 135° split point tip allows for accurate holes with precision starts and less walking. The black oxide coating makes them i for use with portable drills on a variety of materials including metal, wood, and PVC, and they perform effectively even on curved surfaces. This set includes a comprehensive range of sizes to cover many drilling needs. Model Number: 48-89-2801