385 Nm Uv Ultra Violet 21 LED Blacklight Flashlight, 7305uv385 Produces true Ultraviolet (NOT visible) light (wavelength 380-380nm from 9 LEDs w/100,000 hr-life) UV light used to prevent forgery, authenticate documents, illuminate proteins, pinpoint leaks Essential tool for law enforcement, postal inspections, customs, medical forensics, HVAC repair Shock and weather-resistant with silicone seals; lights for hours on 3-AAA batteries (not included)