ArmourLite Tritium Professional Shatterproof Watch

ArmourLite Tritium AL1432 Professional Shatterproof Armourglass Black Steel ArmourLite watches have tiny glass tubes that are filled with tritium gas and then hermetically sealed. The electrons of the gas continuously react with phosphorescent paint resulting in a radio luminescent light source that glows constantly for up to 25 years. No external power source or charging-by-light is necessary to maintain the glow. The glow is completely self-powered.