4 In. Keystone-Tip screwdriver with Heavy-Duty Square Shank. Heavy-duty square shank for wrench assisted turning. Bolster reinforces shank for hard use. Designed for the most demanding uses. Cushion Grip handle allows for greater torque and comfort. Integral flanges inside handle provide solid, twist resistant blade anchor. Special heat treated shafts. Precision machined tip for exact fit. Premium chrome plated for smooth feel and corrosion resistance. Patented Tip-Ident(TM) quickly identifies the type of screwdriver and screwdriver tip orientation. Meets or exceeds applicable ASME / ANSI specifications.