It is an application for you to freely change the color of each RGB, to check the RGB value of the color you are looking for.
Because a color will change by moving the slider, you can just enjoy the color change just it.
This is a useful tool when the developer of iOS to make any color in the UIColor in Xcode mainly.
Color is important in the application of the flat design, but because the number, which comes standard is limited, how about you? Find the color of your choice with this app, if you try to implement?