Tubes with inert gases excited with high voltage. From left to right: Helium, Neon, Argon, Krypton and Xenon. Each tube emits a different color and in Stock Photo - Alamy
Rare Nobel Gas Sealed Tube 99.999percent Luminous Gases Krypton Helium Neon Argon Xenon Oxygen Nitrogen HydrogenElement Collection (M 14x60mm, HeNeArKrXeNHO) : Tools & Home Improvement - Amazon.com
Color guide — Blog — PATRICK NASH DESIGN
High Purity 99.999% Glass Seal Rare Gas Hydrogen H Helium He Neon Argon Ar Xenon Krypton Luminescent Gas Element Collection - Tool Parts - AliExpress
Noble Gas Glow Tubes - YouTube
HMME Rare Nobel Gas Sealed Tube 99.999% Luminous Gases Krypton Helium Neon Argon Xenon Element Collection (5 Pack): Amazon.com: Tools & Home Improvement