Bosch MC10 5/16-Inch by 8-Inch by 10-Inch Multi-Construction Drill Bit Innovative tungsten carbide plate - Suitable for multi-purpose applications. Sharp, Multiple Diamond ground cutting edges - for a high drilling rate, even in hard materials such as tiles and concretes. Sturdy Drilling head - For a long serviced life in drilling and impact drilling applications. New Steep Spiral - Optimized drilling dust clearance in multiple materials. New Customized carbide geometry optimized to handle a wide range of materials.