Bosch 4-Pack Glass & Tile Drill Bit Set is a professional-grade solution for drilling precise holes in glass, tile, and other hard materials. The set includes four drill bits in the following sizes: 1/8", 3/16", 1/4", and 5/16". Each bit is made from high-quality carbide with a reinforced head to prevent cracking and provide a longer life. The 3-flat shank prevents slippage, and the innovative geometry allows the bit to drill faster. This set is ideal for use with rotary drills.