The lock box palette is 11.5"x1"thick. It is great for moving from location to location. Teachers find it helpful for distributing paint to students. The top of this palette locks in position with a secure slide fastener. Inside you can store paints in a circular, segmented plastic tray or on disposable mixing papers designed for this palette. Properly used it can store fastdrying media like acrlics, gouache and watercolor for weeks.