Glows in the dark with and without UV light. Multiball stacks are smooth and easy. Perfect for isolations. Durable and chip resistant for a long life product. Pure acrylic contact ball. Unlike polycarbonate balls, acrylic has no resistance when rubbed against acrylic, making your multiball stacks smooth and easy, and perfect for isolations. These balls are made using optical grade material which is free of internal distortions, seamless, one piece and highly polished. Durable, chip resistant and virtually shatterproof.