I have many watercolors, gouache, and postercolor. I bought this for my poster color to keep it moist. Go ahead and buy the one with the extra hand held palette and the metal stick. The metal stick is great for taming the paints into the deep wells. It has a detachable palette that slides under the box and the clips are sturdy that are used to close the lid. What is neat about this one is that the little silicone squares cap off the well on the inside of the lid. instead of being a confusing and lose silicone seal that goes around each well which could still include leakage. I think with any paint of course you dont want to store it vertically however this offers about 99% protection where you may have time to correct the level of the palette. I would probably still put it horizontal if i were to backpack it somewhere.