Milwaukee® Thunderbolt® Black chemical compound wholesaler length drill bits are designed for extreme sturdiness and long life. The Thunderbolt® internet options a thicker core than a regular bit, that provides final strength and protects against side-load breakage. A specially designed parabolic flute type clears chips and dust quick to stay the bit cool. A exactness begin, one hundred thirty five Split purpose tip starts on contact to stay the bit from walking for quick correct holes. glorious for drilling on recurved surfaces, needs less effort to drill and is very suggested to be used with transportable drills.