100% synthetic glow in the dark hair extensions. Glow in the dark hair will glow brighter if you let it "charge" in the sun or under a bright light for a bit before putting it in the dark.
Glow in the dark hair is also UV reactive, and will glow under blacklight. The UV light from a blacklight will also work for "charging" the hair, the same way that actual sunlight does.
Since this hair isn't kanekalon, dreads made entirely from it may not hold up as well over time, but it will work for streaks or blends. It doesn't shrink down when heated with boiling water or steam like kanekalon does, but it will hold its shape once set.