This easy to set up, inexpensive device was designed by teachers in order to collect the correct proportions of hydrogen and oxygen from the electrolysis of water. Its unique design helps correct issues such as falling test tubes perched over unsteady electrodes and gases escaping due to poor alignment. This product is great for general science teachers, chemistry classes or when teaching concepts such as Mixtures and Compounds, States of Matter, Oxidation Reduction Reactions, Law of Thermodynamics, and Alternative Energy. Each device consists of the electrolysis unit, gas collection tubes and a clear polycarbonate tub. The device will attach to any 6-12 Volt DC power supply (not included) using the alligator clips on the unit�s power leads. Includes activity guide and an instructional CD.