littleBits UV LED

The UV LED Bit sends out a special kind of light. Because of it’s shorter wavelengths, it can filter out certain types of visible light, changing the way you perceive colors. It looks purple to the eye, but it has some special abilities, like making certain materials glow in the dark. In a dark room try shining your UV LED on white fabric, laundry detergent, high-value bank notes (Benjamins?) or scorpions (Yikes!). The UV LED can also make special inks, such as invisible ink, appear visible.

The UV LED or ("Ultraviolet Light-Emitting Diode") Bit emits an ultraviolet light, at 400nm in the UVA spectrum, which appears purple to our eyes.