Gaseous Tritium luminous side dot marker 

These are the deluxe option (sold singly)

these 2mm by 12mm side dot markers are

made of a sealed glass vial containing a quantity of radioactive  

Hydrogen Isotope (Tritium)  

This is a beta emitter and is hence completely safe

the decay gives off light as the hydrogen H3 decays into helium

the light given off is constant and requires no charging  

will work straight out of the case and glow all night and day.

decays slowly over time, expect these to stay bright

 for at least ten years and then fade slowly

giving out usable light for over 30 years.

contained in a sealed vial of borosilicate glass

just drill a hole and glue the vial in place,

this is a gas, don't open the vial, glue it in as it comes.

Ice Blue colour