Feature: Glow in the dark pebbles with up to 8-10hours glow time after being exposed 15-20 minutes to sunlight. A light bulb or lamp line a walkway, edge a flower bed or fill a planter light up your fish tank at night. Swimming pools AQUARIUM, Fish tank Walkways Decor Driveways Flowers garden or backyard decorations, etc. Size: 20-30mm long x 15-20mm wide