Spectrum Tube - Argon. Argon gas-filled discharge tube for studying typical spectra of the different gases and for use in calibrating spectrometers. The glass body is provided with metal end caps and is constricted along the middle portion to concentrate the discharge glow. Tube Length: 260mm. Strike Voltage: 2000V - 4000V. Maximum Recommended Running Current: 3mA. Recommended Run Cycle: 30 seconds on, 30 seconds off. Requires the following equipment to operate:. Spectrum Tube Holder - B8R08098. E.H.T. Power Supply - B8R02653. E.H.T. Safety Experiment Leads - B8R07149. Alternative individual tubes are available to purchase separately:. Helium - B8R06986. Hydrogen - B8A46539. Krypton - B8R06991. Mercury Vapour - B8R06990. Neon - B8A46565. Nitrogen - B8A46541. Oxygen - B8A46553. Xenon - B8R06992. There is also a bundle of 4 tubes available - B8R06832 - Hydrogen, Nitrogen, Oxygen, Neon.