Handheld Uv Black Light Torch Portable Blacklight with LEDUV Black Light Check watermarks and security strips Check paper quality on security documents Highlight alterations and stainingThis flashlight is lightweight and easy to use. It uses long wave UV light that isn't harmful to your eyes. You can uses it to check watermarks and security strips. Check for stains and spots on clothing that need attention. The light uses 4 AA batteries (not included).