Hitachi 725131 1-1/8-Inch Hex 1-Inch x 15-Inch Ground Rod Driver 1-1/8-inch I.D. x 2-1/8-inch O.D. width Made of high quality carbon hardened steel Head hardness of 52-57-HRC allows the bit to achieve wear resistance up to 50-joules. High tolerance milled shank provides a perfect fit Comes with a 30-day limited warranty High Quality Carbon Hardened Steel High Tolerance milled shank provides perfect fit CNC Controlled manufacturing ensures 100% quality consistency