These gas-filled tubes contain Tritium, the inner surfaces of these thin glass vials are coated with a phosphor, by undergoing beta decay the gaseous tritium in these light sources is releasing electrons that cause the phosphor layer to fluoresce.
Tritium pose no external radiation threat via beta radiation when enclosed in non-hydrogen-permeable containers due to its low penetration depth, which is even insufficient to penetrate intact human skin.
The radiation emitted is measured in micro-Sievert, these vials emit about 1 micro-Sievert per hour, to put this into perspective a banana gives off roughly 0.1 micro-Sieverts, in the case of this jewelry the amount or radiation emitted would roughly be the same amount you could get by eating 10 bananas.
These light sources can glow up to ten years without needing any kind of charging.
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