Radioactive 4mm uranium glass Druks beads made in the Czech Republic are supplied in a sealed package of 10, are slightly radioactive and can be detected by our G21276, CJ304, or C8092 Geiger counters. In addition to the beads, you will receive a giant 10mm UV LED and a coin battery. Place the leads of the UV LED across the coin battery (longer lead is +) and the beads will glow brilliant green under the ultraviolet light!