Emergency Exit Sign with battery backup automatically turns on when power goes out to provide 90 minutes of emergency operation. Energy-saving LED light lasts up to 25 years; consumes less than 2 watts and eliminates lamp changes. Sealed; maintenance-free battery with fully automatic charger lasts up to 10 years. Exit sign also offers rugged polycarbonate construction; 120/277 dual voltage operation; and front/rear stencils with snap-out directionals. Mount on ceiling; wall or other surface. UL listed. Products meeting New York City and city of Chicago specifications may be special ordered through customer service.