A 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 flat electrodes. The Voltaic Cell with Eight Electrodes and a Porous Cup comes with the following electrodes: copper, aluminum, zinc, tin, brass, iron, nickel, and carbon. The included porous cup is used to create a dry cell battery. This can be done, for example, by filling the porous cup with a powdered MnO2 and NH4Cl mixture, placing it inside the plastic cup, filling the remaining space in the plastic cup with NH4Cl solution, and inserting a carbon rod electrode into the porous cup and a zinc electrode into the plastic cup. The porous cup is also sold separately as a replacement part.