Tritium cylindrical vials at maximum pressure.
Tritium is a radioactive isotope of Hydrogen. Tritium light sources are radioluminescent and can be bestdescribed as a strong glow. They are self-powered and do not need to be charged via exposure to light, suchas standard glow pellet. Tritium does not in itself emit light but excites phosphors, thereby generatinglight. It is therefore most often encountered in glass capsules with an internal phosphor coating of variouscolors. Green is usually the brightest based on the phosphors and the sensitivity of the human eye. The halflife of tritium is 12.32 years which means that a tritium based light source will be half as bright after 12.32years.

Tritium lightsources are illuminated by means of borosylicate glass tubes covered on the inside with phosphor powder and filled with gaseous tritium. The gaseous tritium emits electrons, which activate the phosphor powder producing light for 15 years (131000 hours).
Available in colours as follows:

Size: 23mm x 3mm
Can be used as a upgrade for Glow Fob light source or to make your own keyring fob using Crystal Clear holders for Tritium Vials.
Please see some ideas how Tritium Vial can be used:
Tritium Keyfob Review and INSTALLATION OF TRITIUM INTO GLOW FOB