The 29-Piece Thunderbolt® Black Oxide drill bit set is designed for extreme durability and long life. The Thunderbolt web features a thicker core than a standard drill bit to provide strength and protect against side-load breakage. A parabolic flute form clears chips fast, while the 3-Flat Secure-Grip™;;; shank holds the bit firmly in the drill chuck. The 135° split point tip delivers a precision start and prevents walking for fast, accurate holes. Effective for drilling on curved surfaces, the set comes in a resilient case and includes bit sizes 1/16", 5/64", 3/32", 7/64", 1/8", 9/64", 5/32", 11/64", 3/16", 13/64", 7/32", 15/64", 1/4", 17/64", 9/32", 19/64", 5/16", 21/64", 11/32", 23/64", 3/8", 25/64", 13/32", 27/64", 7/16", 29/64", 15/32", 31/64", and 1/2".