Easily the most common type of sign. This type of sign is usually vinyl lettering on almost any type of flat material. They may be a standard rectangular shape or they can be contour cut for a more decorative look. A flat panel sign is very versatile. Its uses are virtually unlimited. From inexpensive corrogated plastic to marine grade plywood & aluminum,there is a material to fit any budget. Add some 3 dimensional letters for a sign that will really stand out.