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 glowinthe dark pebbles, you can release your imagination, youcanmakeagorgeousfairy fish tank or garden. Features - Color: Mixed color. - Material: Resin. - Size: About 2.50X1.80X2.00 cm / 0.98X0.71X0.79 inch. - Put the pebbles under light when you receive it, pebbles can glow if you put it in dark. - All stones come into different shape, very funny for decoration. - Valentines Day decoration, line a walkway, a flower bed or fill a planter with these glowing stones that will glow in the dark after being exposed to daylight. - 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. - These glow pebbles absorb and store energy from sunlight or other light sources and light up in dark environments.