Thunderbolt titanium coated drill bits are designed for extreme durability and long life. The Thunderbolt web features a thicker core than a standard drill bit, which provides ultimate strength and protects against side-load breakage. A specially designed parabolic flute form clears chips and debris fast to keep the bit cool. A precision start, 135 Split Point tip starts on contact to keep the bit from walking for fast accurate holes. 3-flat secure-grip shank holds the bit firmly in the drill chuck for reduced slipping. Excellent for drilling on curved surfaces, requires less effort to drill, and is highly recommended for use with portable drills. For all masonry materials. Thanks for shopping Hipp Hardware Plus's Online Store for all your DIY and Home Improvement needs. Remember Hipps Help!