Features and Benefits:?For use in Spline Drive Rotary Hammers?10 inch length x 5/8 inch x 3/4" Rod Diameter?3/4 inch Hex with 21/32 inch Round Shank?Ground Rod Driver?Made from forged high grade steelDrop forged of high grade steel, this hammer iron is used by utility companies to bury grounding rods in the soil. Internal diameter of the ground rod driver and capacity of the hammer determine the size of ground rod able to be installed. One per package.