Up to 50x tougher than a Bosch 2607001528 Extra Hard bit.Do you need Phillips screwdriver bits for your next screw-driving job? Bits that last a long time and perform well in heavy-duty applications? Try PRO Impact PH. We designed them for strength and resistance to high torque.PRO Impact PH screwdriver bits are an excellent choice for installers looking for robust screwdriver bits for heavy-duty applications. The bits are made of heat-treated modified steel for excellent strength and resistance to high torque. Their torsion zone absorbs torque stress at the tip of the bits to ensure they do not break. They have colour-coded rings indicating the head type and laser markings to help you choose the size you need.1/4" impact-resistant hex shank for use in impact drivers and drill/drivers