Internal flanges provide solid, twist resistant shaft anchor. Patented Tip Ident quickly identifies nut driver and size. Handle end is also color coded for easy identification. Cushion Grip handle allows for greater torque and comfort. Meets or exceeds applicable ASME / ANSI specifications. Premium chrome plated for smooth feel and corrosion resistance. Full hollow shaft facilitates work on stacked circuit boards or other long bolt applications. 5/16 In. Hex Size.