Just another cool item I found on AliExpress - a TC4 titanium milled bead, that has a tritium vial inside, making it visible in a complete darkness.
Tritium is unique as a light source, because it doesn't accumulate light (like other luminophore, that stores light and then emits it for a limited period of time, this can be found on a lot of watches), but is itself the source of light, that emits light all the time and can last up to 25 years.
Check it out here: https://goo.gl/q25sRs
Titanium tritium lantern can be bought here: https://goo.gl/Yuys81
Budget plastic tritium lantern here: https://goo.gl/5LjR36