The bosch pro 20 piece impact hss drill and screwdriver bit set is a professional-grade mixed bit set designed for heavy-duty screwdriving and long-life drilling in metal, ideal for interior fitters and installers. The screwdriver bits are manufactured from heat-treated modified steel and feature an extended torsion zone that absorbs torque stress at the tip, helping to prevent breakage during demanding impact driver use. Colour-coded rings and laser markings make it straightforward to identify the correct bit quickly on site. The hss-g metal twist drill bits are ground from solid high-speed steel, offering resistance to wear and consistent drilling progress through metal. All bits feature a 1 4 impact-rated hex shank, making them compatible with both impact drivers and drill drivers. The set is supplied in a pick and click case, keeping bits organised and easy to locate between tasks. With a comprehensive selection of ph, pz, and torx screwdriver bits alongside four twist drill sizes, it covers the most common requirements for interior installation work. Features and benefits: extended torsion zone absorbs torque stress at the screwdriver bit tip to prevent breakage heat-treated modified steel construction for strength and high-torque resistance hss-g twist drill bits ground from solid steel for durability and fast drilling progress in metal colour-coded rings and laser markings for quick, easy bit identification 1 4 impact-rated hex shank compatible with impact drivers ...