500 UV Reactive Pony Beads. Changes colors when exposed to sunlight. 9x6mm with large 4mm hole Before sun exposure they are almost white. After being exposed to sunlight they turn vivid colors. More intense the longer they are exposed to sun! Not as vivid indoors or in the shade. Awesome Hairbeads! Great for Beadie Critters, Keychains, necklaces, bracelets and much more.