The most unique and non polluting energy sources you can find on earth - the potato, salt water and mud. Be amazed at how they light up a bulb or sound a buzzer with the 4M Enviro Battery. Includes: 3 zinc plates, 3 copper plates, connection wires, 3 plastic cups, a light tower, LED lamp, sound chip, experiment record sheet, adhesive tape and detailed instructions. Age 8+ years. Part of the Green Science range. Distributed in New Zealand by Holdson.