These small battery powered lights are cast in glow in the dark, translucent urethane.
These clusters come with a small LED tealight that can be set to flicker like a candle, flash or have a steady glow. It is turned on with a button at the top of the tealight itself and is then snugly placed into the crystal. You can also use a remote control for these lights if you want more convenience ( buy it here) .
When these lights are charged with UV /sunlight they will glow in the dark. You could hang these lights from your ceiling, have them on a book shelf or desktop.
