For use with electrovoltaic cells or in various other chemical, physics and chemistry experiments. Each metal electrode measures about 120mm x 18mm x 0.75mm (5″ x 1/2″ x 1/32″). Metals include Iron, Copper, Zinc, Brass, Aluminum, Bronze, Steel and Magnesium.WARNING: Metal electrodes have sharp edges. Not a toy!. Handle with care.