Spectrum discharge tubes contain gases that, when ignited, emit different waves of light (or the gas's spectral lines). This is how scientists are able to determine the gaseous make-up of planets in our solar system. This nitrogen spectrum discharge tube is approximately 10.25 inches long with electrodes sealed at both ends that are connected to lead wires protected by metal caps. It needs an induction coil spark of approximately 5cm or a suitable power supply for use. Recommended for use by adults only, this is excellent for use in classroom demonstrations or college-level science projects.