Bundle: 2 Packs: Clear and Blue Over 1,100 Balls; Watch the Tiny Beads Grow in the Water and Glow-in-the-dark Magic Trick 2 packs (Clear and Blue, total over 1,100 Balls) Amazing Cosmo Beads(tm) Glow-in-the-dark Water Marble Balls;Great for Gift Giving As Stocking Stuffers. Kids of All Ages Will Love'em. Yup, they Grow in the water, and 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. Magic and a great tool for when you teach/learning water cycle , evaporation and Science educational products Non-Toxic, 100% Biodegradable, Non-Flammable. Reusable up to 2 years: can be reused over and over again by allowing them to dry out and re-hydrating them like the first time use.