A color wheel or colour wheel is a visual representation of how colors can be categorised by correlating hues on the color spectrum. They are often used to teach about primary colors, secondary colors and complementary colors. When the color circles form a cylindrical shape it is referred to as either an artist palette or artists' wheel.
The color wheel picker does just what its name suggests; it allows the user to choose a color from the circle. The user can do so by clicking on the desired hue and then clicking at its point on a 360-degree line of all available hues. This is an interesting tool for artists because it gives them options that they might not have considered before, like lighter shades or complementary colors.
It's also helpful for people who work with designing websites or developing graphics, as it will help them make sure their palette doesn't clash against other elements in their design.