These two-sided 4" x 12" aluminum flag mounted photoluminescent fire extinguisher arrow signs are energized by ambient light and will illuminate the instant lights go out. These glow in the dark location signs are perfect for corridors and large open areas to ensure your fire extinguishers are easy to locate in the event of a power loss or fire emergency. The photoluminescent material is charged by common light sources such as daylight, tungsten filament and fluorescent lights. One hour of exposure to ambient light source will sufficiently charge the photoluminescent sign to glow brightly for more than 8 hours.