Designed as a reference tool to provide easy, desktop access to all 216 web-safe colors. The wheel lists all HTML and RGB values right on the color you select. Unique and easy to use for amateurs and professionals. Also illustrates color relationships, includes a value scale, and is UV coated for protection and durability. The Web Color Wheel features:Complementary colors--colors opposite each other in the RGB spectrum. Analogous colors--colors that lie side by side in the RGB spectrum. Value Scale--illustrates levels of gray and shows relative values.Triads--basic color combinations consisting or primary and secondary RGB hues.7 3/4 in. (19.7 cm) in diameter.