designer's own words:Generally color sprays are filled only one color in each therefore; plenty of spray cans are wasted after one use while people are using it. "Color dial spray" is a new type spray which is composed of "CMYK"color catridges in one. It can maximinize convenience of use and portable ability. The user canimmediately change the colors by dialing the color dial whhich is embeded on the product. There are two dial sections. one for the "Hue" and the other one for the "Brightness". So it helps you to get the whole colors you want. Moreover color catridges of it can be refilled many times over. It helps us reduce enviromental distruption as well.