resin, these glow in the dark pebbles. There is no power or battery required for these environmentally friendly solar luminous rocks glow stones. All they need is just sunlight to absorb enough ultraviolet light before they can shine in the dark. Can be used to decorate potted plants, fish tanks, swimming pools and gardening, etc. With our glow in the dark pebbles, you can release your imagination, you can make a gorgeous fairy fish tank or garden. Features - Color: Dark blue. - Material : Resin. - Size: About 2.5x 1.2 x 0.2cm. - Glow in the Dark: Put the pebbles under light when you receive it, about 10 minutes later, pebbles can glow if you put it in dark, easy to use. - Safe and exquisite: Resin material, smooth body, no harm. - Mixed Color: Each pack comes in different color mixed, enrich your decoration. - for fish tanks rocks pebbles gravel, glow decor, ponds, yard, waterscapes, landscape decoration, potted plants, lighting a pathway or driveway, fairy garden glowing stones, crafts, etc. - Warm Tip: Dear buyer, due to lighting effect, monitor's brightness, manual measurement, etc., there could be some slight differences in the color and size between the photo and the actual item. Sincerely hope that you can understand