The Whirlwind is a heavy-duty single-sided wing sign for displaying indoor or outdoor graphics. It has a wheeled, compact molded base that can be filled with water or sand. The snap frame poster holders make changing the graphic quick and easy. Spring-design flexes to withstand wind. Front loading snap frames constructed from aluminum and powder coated steel. Padded base holds 7.5 gallons of water. For use below 40 degrees Fahrenheit, use sand.