#18 925 This pendant glows blue when charged buy light

The first 2 pictures show the pendant when charged by the flashlight for 10 minutes. The last 2 pictures show the pendant not charged. it's a cool necklace I don't know how long the charge lasts as it depends on how long it has been exposed to light. can be charged with a light bulb, flashlight, sunlight, etc. UV light works best.