Aside from my vintage (Made in the USA) crimping pliers, this is probably my favorite tool - you should definitely get one!
Not only does it finally clarify what color the tints and shades we tend to call "neutral" (beige, browns, tan etc) really are, but it also uses triangles and rectangles on the moveable inner wheel to direct you to a nearly infinite number of color harmonies.
It comes with quite a hefty little instruction booklet in English, French and Spanish.
Choosing a selection results in a full page refresh.
Press the space key then arrow keys to make a selection.