Copper bonded earth rods are made from low carbon Steel. Earth Rods are molecularly bonded with 99.9% Pure electrolytic copper. Perfectly Bonded rod will last longer, drive easier and will not crack. Corrosion resistance while providing the lowest resistance to ground. Threads are rolled by roll threading process, which ensures that even copper covering is maintained, even at the roof of the thread. Roll thread gives greater strength than cut thread.