Different color of reflected light can be observed in experiments, when the same kind of ultraviolet light respectively irradiates the fluorescent mark of true and false currency.

But unlike its predecessors, Scale doesn't also wash away the signals of fluorescent proteins, which scientists use to mark neurons, blood vessels, and other small structures in the body.

A fluorescent layer arranged in the inner part can play the navigational function, and the color can be changed as a special mark.