About Tritium tube: A Tritium tube is an artificial light source powered by the radioactive decay of tritium (H3) gas. The Tritium tube consists of a glass container filled with tritium gas. The inside walls of the enclosure are coated with a phosphor. As the tritium decays, it emits Beta particles (high energy electrons). These electrons stimulate the phosphor, causing it to glow. No external power source is required and the lights are very reliable. This has led to their broad application in emergency exit signage. The lifetime of a betalight is limited by the half-life of the tritium gas (12.3 years); the light will glow with exponentially less light over time, but the service lifetime of betalights is usually quoted as ten to fifteen years. No external radiation is produced during normal operation, although rupture of the glass capsule will release the radioactive tritium gas contained within. Because of this, used betalights should be returned to their manufacturer rather than being incinerated or landfilled. Technical Specifications: Material: Tritium gas , Plastic box Color: As the picture shown Size : 6mm x D1.5mm Waterproof: 100m Light range: 7-8cm Brightness: green > blue > white > yellow > orange > pink > red > purple Features and Benefits: - Glows continuously for 25 years. - Bright and visible unique clear white glow. - Completely contained and self-powered. - Perfect for sign light, decorations, horologe, luxury and glasses. Usage: Can DIY all kinds of decoration, collection, outdoor supplies, car night recognition etc. Notice: 1. Please allow 1-3mm error due to manual measurement.Pls make sure you do not mind before you bid. 2. The color may have different as the difference display,pls understand. 3. THIS ITEM IS NOT FOR LIGHTING PURPOSE. IT ONLY FOR MARKING IN DARKNESS.