The unit is supplied with 7 at Electrodes and include; copper, aluminum, Zinc, Tin, Brass, iron and nickel, round carbon rod and a porous cup. The voltaic cell is ideal for demonstrating the characteristics of a primary cell. The cell's cup is clear so you can easily view the electro-chemical reactions taking place. The top rim is made of heavy molded plastic with a sturdy nickel plated clamp that holds both round and at Electrodes.