Ultraviolet is used to test depression glass, gemstones, pottery repairs, carbon stains on metal; ages of quilts, ivory and others. What's more, you can easily spot all these fluorescable items -- many of which cannot be detected by the human eye without the use of these black light lamps as they will glow in the dark. Can be used to identify counterfeit money. Mark your electronics, computers, jewelry, antique collection with our invisible black light ink pen for security and if stolen for later identification! Perfect for night Disc Golf or Geo Cache! FISHERMEN find your fluorescent fishing line and lures while night fishing our ultraviolet head lamp. Charge your lures with a black light.