Solar UV Beads, 800 pcs of 12/12mm round blue beads for kandi kids and crafting. Around 800 pcs of 12/12mm big round blue beads. Weight: 1.2 lb Beads change color when detecting ultaviolet in the sun, and change back to plain without sun Beads change color when detecting ultaviolet in the sun, and change back to plain without sun. It helps to remind our children to put on sunscreen when the beads color turned really bright. Great to DIY bracelet, necklace, ankelet, and pony/hair blaits.