Yeming's Photoluminescent Signs require absolutely no batteries, electricity, or external power thanks to our advanced photoluminescent technology. It is thanks to this feature that our photoluminescent signs are completely fail-safe, as they quickly charge from exposuring to external light for 5-10 minutes and then glow brightly for more than 12 hours in the event of a power failure,which can help to overcome the problems in emergency evacuation caused by lack of visibility and disorientation in smoke conditions,so they are widely used in Tunnel,Supermarket,Gymnasium,Subway,Underground parking garage,office building and many other public places.