CITIZEN'S Solid copper earth rods are made in two types. Externally threaded and internally threaded. Solid Copper earth rods are used where the factor of corrosion is very high and exceptionally long life is required. Hence these rods are manufactured from pure and high conductivity hard drawn copper as per BS 2874-C 101. These rods are also available with tin plating in order to reduce the risk of oxidation and increasing self life.