... composed by coupler, driving head and driving stud. Earth Rod Clamp:1) Coupler:Use good quality brass ... after thermal refining, length is 70mm, used between earth rod and driving head.2) Driving Head:Use 45 ... # carbon steel after quenching, it touch the surface of hitting, protect the surface, and also relieve the ... , and use thread tightening on one head of the earth rod, good for hitting deep in ...