The dimensions of the box are as follows; Closed: 9 1/2" x 4" x 7/8", open: 9 1/2" x 12".  Each box comes with 15 mixing wells. There are three mixing areas on the lid as well as a removable mixing area next to the thumb hole. There is a large mixing area on the flap.  Included with each box is a quality cloth bag with drawstring. This palette has many options regarding customization. Adding more wells. Replacing the thumb hole with a mixing tray. Varying the size of the paint wells. These are a few of the options available.