This movement tray is composed of 2 layers of 3mm MDF. The tray holds 12, 15mm square bases in two rows of 6. The spacing allows for models that overhang their bases. The spaces are slightly larger than 15mm to allow for extra paint or material that may be on the base. We use high quality MDF which does not warp when primed, painted and decorated to match your base design. The tray comes unassembled and requires either wood or super glue to assemble.