Diablo, 4 piece tile and stone carbide tipped drill bit set. Set consists of 1/8", 3/16", 1/4" and 5/16" drill bits. Diablo's tile and stone carbide tipped drill bit range provides faster starts and longer life in tile, stone and glass. Optimized with a unique brazing and hardening process, the carbide tip extends life and productivity, allowing users to drill fast, accurate holes. The multi-ground carbide tip design allows for aggressive starts that produce clean holes when drilling into hard materials. The 3-flat shank provides extra stability by eliminating spinning in the drill chuck.