... Sign, Cast Aluminum - Single or Double Sided - Self Testing- AC w/Battery Backup Specification:Material: Alluminum Alloy: 1x,2x, 3x, 4x ... , 6x, 7x seriesTemper: O, T1, T4, T5, T6, H12Shape:Rectangle Shell/ Case/ HousingSize: Flexible SizeSurface Treatment: Anodized, Power Coating, Sandblasting, Polishing ... Sign, Cast Aluminum - Single or Double Sided - Self Testing- AC w/Battery Backup