Spectrum Tubes These tubes produce bright, well-defined, unique spectra when the gas inside is excited before a spectroscope. Of glass construction, 26 cm long and narrowed to capillary width for about 10 cm in the center. Sealed metal wires hold the electrodes and are welded to metal caps which have a loop for convenient hookup to wire connections. You need 614-0795 Spectrum Tube Power Supply, not included. Varieties as shown in table below. Qty :