Because it's attractive, durable, and treated to withstand the elements in high-moisture environments, we use MDO: Medium Density Overlaid Plywood. This overlay resists water, weather, and wear. Paint finishes on MDO last as much as three times longer than the same finish applied to ordinary plywood. MDO has an exceptionally smooth finish. These properties make it ideal for hand painted signs. Each side is primed and painted with high quality, UV resistant paint. Edges are sealed, primed, and painted. We guarantee our signs and your satisfaction.