The Klein Tools Heavy Duty Nut Drivers feature a fully hollow handle design, which allows for fastening nuts on unlimited lengths of threaded rod. The nut drivers have magnetic tips to help retain the nut while driving, and wrench assist for additional torque. The heavy duty shaft has a cushion grip handle, and each nut driver end is color-coded to assist identification. The nut drivers are available in six individual sizes - 1/4”, 5/16”, 3/8”, 7/16”, 1/2” and 9/16” - as well as 4-pc and 6-pc sets.