The classic demonstration of spectral lines. Each tube has its characteristic spectrum when energized before a spectroscope. These tubes acquaint students with the spectra of common g in their pure form, as well as for demonstrating wavelength. The glass tubes are 25cm long with the capillary portion about 10cm 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.