This is an empty version of my favorite folding palette that is featured in my Custom Watercolor Palette. This is the best palette that I have found for watercolor in the field. In fact, for years, I have used this palette for both my field work and my studio work as well. This Holbein 24-well folding plastic palette is 3-3/4″ wide by 10-1/4 inches long with five separate mixing areas (and a sixth that folds out). It is sturdy, durable, slim, and lightweight.
See my blog, Watercolor Choices, for a full list and description of the colors on the palette I use in the field and in my studio.