This Ultraviolet Marker can write invisibly on almost any dry surface, including metal, paper, glass, paint, skin, and currency. The markings remain invisible until illuminated under an ultraviolet light source. Ideal for marking personal property, sensitive notes, thief detection, and covert communications. The ink is heat-proof, waterproof, and non-toxic. Ink colors: blue.
See our article "Using UV For Bug-Out Security" HERE.