The classic demonstration of spectral lines. These tubes acquaint students with the spectra of common gases in their pure form and are also used for demonstrating wavelength. Each gas has its own distinctive set of spectral lines when energized and viewed through a spectroscope. A spectrum tube power supply (not included) is required to energize the tubes. The glass tubes are 27 cm long with the capillary portion about 5cm long. An electrode is sealed in each end and attached to a metal end cap with a loop for convenient hookup to wire connections. Each spectrum tube includes an activity guide.