1972 Grumbacher Color Computer Color Wheel

I love all things having to do with color and color theory, so had to grab this very 1970s Grumbacher "Color Computer" when I came across it at the PaperTown show last week. Color mixing on one side and color harmonies on the other, with turning dials to cycle through the whole spectrum. Once the property of a Gerri McCrary-Morgan, who wrote her name on both sides 

9 3/8" in diameter. Good overall used condition, with a few light stains and a few clear tape mends. Works as it should!