The Color Harmony Wheel is great for figuring out what colors go together, and the complement to a particular shade. Just center your main color in the big pie shape on the wheel. The complement is in the cup shape opposite your main color. The two dots on the spinner indicate clashing colors that can be effective in jazzing things up--just a pinch if you dare. Even works well when you're using neutrals, because those are on the inner ring. The spinner keeps you from using colors that will not harmonize, because it blocks them from sight. There are 5 primaries, not 3, evenly spaced around the wheel presenting the color spectrum in much greater detail than a standard triadic color wheel. Of particular interest is the listing of 'standard' paint colors by name (i.e. Prussian Blue, Cobalt Blue, etc.) illustrated on the front of the wheel, showing where they fall in relation to each other! Simple, broad instructions are listed on the back of the wheel. 8"x10"