Bosch Drill Bit Set T4042 42 Piece Mixed Impact Tough (1 4 Inch Hex Shank High Performance Tool Steel Driving and Drilling Professional Kit) Concrete Buggies Tri Metal Shock Resistant Brazing: Silver copper silver brazing Tri Metal Shock Resistant Brazing: Silver copper silver brazing layer absorbs severe impact force to prevent carbide tooth loss during high speed ripping High Quality Construction: Forged from high carbon steel for professional grade durability and performance ensure the impact driver is set to the correct torque setting and keep the bit aligned perfectly square to the workpiece throughout the entire driving cycle The Bosch T4042 42 Piece Mixed Impact Tough Drill and Drive Bit Set provides a comprehensive industrial grade collection of fastening and boring accessories engineered for high torque impact driver operation