Up to 50x more robust than a 2607001528 Extra Hard bit from Bosch. Looking for a compact and reliable screwdriver bit set that you can use for heavy-duty applications? Then try the PRO Impact Set. The set contains the bits you need for most screwdriving applications. The PRO Impact Set is an excellent choice for installers who need robust screwdriver bits for heavy-duty applications. The bits are made of heat-treated modified steel for excellent strength and resistance to high torques. 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. They come in a sturdy case and are arranged in holders that allow you to build your own toolkit. 1/4" impact-resistant hex shank for use in impact drivers and drill/drivers.