1pcs 1.5x6mm Trit Vials Tritium Multicolor Self-luminous 15-Years
It’s now in flash sale for $5.95 ($8.99)
Offer exires in 5 days and 10 hours.
For those how do not know: those are GTLS (Gaseous Tritium Light Source) and do not need light exposure for “recharging” like photoluminescent markers.
Tritium is hydrogen isotope undergoing radioactive decay which produce small amount of electrons that light up the phosphor that covers inside of the vial.
It is completely safe as radiation do not even have enough power to penetrate human skin.
You can read more about that here: [wikipedia] Tritium radioluminescence
Many high-end flashlights include precut tritium slots like JETbeam II PRO Copper Xp-l Hi Anniversary Limited Edition 510Lumens Tactical EDC LED Flashlight two posts above: