... 4.Color: red,green,blue,purple,yellow,black,transparent UV led keychain light:red,green,blue,pruple,yellow,black,transparentPlease see ... the specification of the uv led in the following: UV LED E Series : Part NumberSize (MM)Working Current ... 4-4.0415-4208-9MW201.Application Fields for the uv led keychains:1)Detecting Currency2)Revealing Hidden Knowledge in certain letters ...