resin, these glow in the dark pebbles are odorless, and no radioactive substance. 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: As shown. - Material : Resin. - Size: About 2x 2 x 2cm. - Glow in the Dark: Put the pebbles under light when you receive it, pebbles can glow if you put it in dark. - Eco-friendly Material: Resin material, no harm. - Unique Shape: All stones come into different shape, very funny for decoration. - 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. - No electricity needed These glow pebbles absorb and store energy from sunlight or other light sources and light up in dark environments.