Set features 4 bits: (1) 1/8, (1) 3/16, (1) 1/4, (1) 5/16. Diablo Tile & 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.