Glow-in-the-dark, Color: Clear ;Amazing Cosmo Beads-water Marbles ;Great for party,Gift Giving. Kids of All Ages Will Love'em. by Cosmo Beads Brand: Cosmo Beads, About 500 beads; Size: Dry: 2.5-3.0mm. Hydrated: 1.5-2.0cm Glow-In-The-Dark COSMO BEADS! A novelty item for kids of all ages. Simple directions make them ideal for anyone to use; the young/elderly. Yup, they glow in the dark by placing them under direct sunlight or light source in the room for 5-7 hours before or after hydration. The longer exposed to light the longer they'll glow. Have Fun Learn Science,Toys-Games refill,Fancy Package great for gift. These beads are really cool wet and wacky, soft and squishy, fun and funky, bouncy and beautiful. They start off hard and tiny. Add water and watch them grow to more than 100 times their volume. While they grow have fun never ends. Eco-Friendly Non Toxic. Reusable up to 2 years