This 365 nanometer longwave UltraViolet LED carabiner is an excellent pocket-sized source of a UltraViolet-A! Enjoy hours of operation! At 6 ft. it produces a 20 in. diameter footprint of UV-A light.
Most LEDs claiming to be ultraviolet are actually 395-400 nanometers which is the very end of the ultraviolet spectrum and the beginning of the visible light spectrum. True longwave UV-A ultraviolet is 365 nm. As you can see in the top photo 365 nm reveals the hidden security markings whereas in the lower picture 395 nm does not.