We have the best UV LED blacklights made for detecting false currency. Counterfeit notes are a major problems and if you accept them you put your self at risk of jail time. They are very series about this particular crime to prevent the collapse of faith with the money system. If you have a different need for a UV flashlight, then you can choose between a single wavelength models or one that has selectable wavelengths.
When the wavelength decreases you will get two things. First, the contrast is improved and second the price of the LEDs increases pretty steeply. If you have a wavelength specification from the supplier of a dye product, then follow their recommendation and let us know what that is so we can help. The more LEDs, the more UV power is emitted. For applications where you require multiple wavelengths in one unit, for example white, blue, and ultraviolet, then look at our multi-wavelength selectable units or send us your requirement specifications.