The inside of the 'top' of the case it grooved for color mixing. There is a thumbhole in the middle of the pans holding the colors. The colors are arranged chromatically, with a diagram of the color wheel just inside of them to assist in color mixing. Also in the case is a small, approximately size 3, round brush with fine, natural hair bristles. Closed, the case is 4 1/2" across. Opened, it is 9 1/2" x 4 1/2".