S119 Square Recess Screwdriver Bits Impact Bulk Square Recess (also known as Robertson) screwdriver bits are very popular. The head has a slight taper which prevents cam-out and holds the screw more securely. Sutton Tools Supabit Extreme Impact Bits Certified heavy hitters specifically developed for use with the high-torque output of an impact driver. Square Recess tip: slight taper prevents cam-out and holds the screw more securely Magnetic tip increases productivity and eliminates frustration when working at awkward angles or in tight spaces 3X torque: Torque tested to exceed DIN standards by up to 330% 1/4" hex shank with power groove for use in impact drivers and quick change adapters. 1/4" hex insert with retaining notch for use in bit holders and hand drivers Cold forged from premium shock-resisting S2 tool steel with a hardness of 58-62HRC for superior strength Manganese Phosphate coating for highest hardness and superior corrosion and wear resistance