Apex hex extensions feature a male 1/4", 5/16", 7/16", or 5/8" hex drive shank on one end, and a 1/4" male square drive output on the other. Use these handy extensions with your favorite female drive power tool to increase the reach of your impact sockets. A handy pin or ball type type retainer keeps impact sockets securely attached to the extension during operations. As with all Apex fastener tools, these high quality extensions are made in the USA.